Patent Application
20060011621
The present invention relates to a microwave oven, and more particularly to an exhaust ventilation system for a microwave oven configured to be mounted above an oven range.
Conventional microwave ovens are generally classified into several different types including: tabletop microwave ovens designed to be seated on a table and/or countertop; and a ventilation hood-combined microwave oven designed to be mounted above a oven range—sometimes referred to as Over-The-Range (OTR) microwaves. An OTR microwave includes a ventilation hood type system for exhausting hot air, steam, smoke, etc. generated from the oven range. The ventilation system for a typical OTR microwave normally includes a suction opening, which is frequently provided with a grease/smoke filter, located along the bottom surface of the OTR microwave. Exhaust air flow is drawn into the suction opening and is passed around the microwave oven cavity and is directed either back into the kitchen environment through an exhaust outlet opening or is directed to an external exhaust.
U.S. Pat. No. 6,433,324 discloses an exhaust flow passage system for an OTR microwave oven having an oven cavity surrounded by a outer case. In the background of this patent, various prior art systems are discussed for providing airflow passages along both sides of the microwave oven cavity and the outer case. This patent further describes and claims an OTR microwave oven having an exhaust airflow passage provided solely along one side of the oven cavity—between the oven cavity and outer case—opposite an electric equipment installation chamber.
U.S. Pat. No. 4,327,274 also discloses an OTR microwave having a bottom vent openings provided with air intake filters wherein a blower draws exhaust air in through the vent openings and directs the exhaust air through a passage between the back wall of the microwave cavity and a rear cabinet wall. The exhaust air then exits the microwave assembly through either a top or rear outlet opening, depending on the installation configuration.
U.S. Patent Application 2003/0218011 A1 discloses a wall mounted microwave oven having an exhaust fan assembly which increases an internal cooking chamber volume. This is accomplished through a fan assembly system mounted along the upper, rear corner of the microwave and which protrudes upwardly from the oven body.
The present invention is directed to a wall mounted type microwave oven having an external enclosure including a bottom closure wall which includes a suction opening and a top vent opening and an oven cavity which is supported within the external enclosure. The oven cavity has a rearwardly stepped portion to maximize the usable space provided within the oven cavity. An air exhaust air path is formed between the external enclosure and the oven cavity and includes a bottom plenum, a pair of rear air channels and an upper plenum. At least one blower is provided within the external enclosure for drawing air into the bottom plenum through the suction opening and exhausting the air out through a top exhaust opening which forms part of the top vent opening. The rearwardly stepped area divides the space between the oven cavity and the external enclosure into the two rear air channels which receive an exhaust air stream from the blower.
The invention may include at least one filter cover provided over top vent opening. The filter cover preferably has a frame supporting a filter mesh interior. The filter cover can be removably fitted within a depressed region provided about the top vent area such that the filter cover is positioned below a top surface of the enclosure. A plurality of louvers are provide across the top vent opening below the filter cover for supporting the filter cover and directing air flow.
The microwave oven of the invention may further include a side compartment formed between the side wall of the external enclosure and the side wall of the oven cavity. The side compartment is isolated from the air exhaust path such that the exhaust air stream does not communicate with the side compartment. An electrical equipment chamber is set within the side compartment. A cooling blower mounted within the side compartment for drawing air into the side compartment through the top inlet opening which forms part of the top vent opening. By providing the air exhaust path along the bottom plenum, the two rear air channels and the upper plenum and by having the air exhaust path not occupy any space along the sides of the oven cavity a maximum oven cavity width is achieved.
The present invention will be more apparent from the accompanying drawings, which are provided by way of non-limiting example and in which:
Referring to the drawings, there is shown a ventilation hood-combined microwave oven 10 designed to be mounted to a wall above an oven range, sometimes referred to as an Over-The-Range (OTR) microwave or wall mounted type microwave, in accordance with the present invention.
Looking at
The oven cavity 12 includes side walls 30 and 32, rear wall 34, a top wall 36 and a bottom wall 38. The cavity 12 is provided with a front access opening closable through operation of the pivotable door 26. Preferably, the height of the oven cavity (H) is maximized within a predetermined or predefined overall height of the enclosure (H2). The door 26 forms a front surface of the microwave and may extend along the full height (H2) of the enclosure. Rotatably supported within the oven cavity along the bottom wall 38 is a turn table plate 42.
The oven cavity 12 is designed to maximize the cooking volume within a fixed or predetermined total overall size of the microwave oven 10. It is desirable to have the diameter (D) of the plate a maximum size while at the same time minimizing the overall depth (D2). In order to accomplish this objective, the rear wall 34 of the oven cavity 12 has a rearwardly stepped portion 44 which includes two angled wall sections 44a and 44b and a center section 44c. This rearwardly stepped portion 44 extends toward and approaches the rear wall 20. The plate 42 is rotatably supported so that it partially extends into the rearwardly stepped portion 44.
An exhaust ventilation system is also provided as part of the microwave oven 10. The exhaust ventilation system includes an air exhaust path, generally referred to at 48, which includes a bottom plenum 54, rear air channels 60 and 62, and an upper air plenum 64, as described hereinbelow. A pair of blowers 50 and 52 are located along the rear portion of the air plenum or space 54 which is formed between the bottom closure wall 24 of the enclosure 14 and the bottom wall 38 of the microwave oven cavity 12. The bottom closure wall 24 extends horizontally forward from its connection with the rear wall 20 to a crease or bend line 56 to provide an enlarged space along a rear portion thereof for locating the blowers 50 and 52. The blowers 50 and 52 include blower wheels 50a and 50b that have their longitudinal axis extending parallel to the plane occupied by the rear wall 34 and bottom wall 38 of the oven cavity 12. The blower wheels 50a and 52a, in turn, are carried within an air channeling housings 50b and 52b. While two blowers 50 and 52 are shown, it can be appreciated that only a single blower could also be used, or a pair of blower wheels driven by a single motor.
The blowers 50 and 52 operate to draw air into the blower wheels 50a and 52a in one direction and to direct the same air away from the wheels in a direction approximately 90 degrees displaced from the direction of flow of the entering air. By positioning the relatively large diameter blower wheels 50a and 52a in the enlarged rear portion of the plenum 54, the bottom closure wall 24 is permitted to slope upwardly toward the front. In this way, greater visibility of the space underneath the microwave oven 10 is provided. Moreover, by locating the blowers 50 and 52 in the preferred lower rear corner position as shown, an intake air stream 58 is created which takes a right angle turn in the air exhaust path through the blower wheels 50a and 52a. Changing the direction of an air stream flow results in a air flow resistance or efficiency loss. By locating the blower wheels 50a and 52a at the 90 degree bend in the path of the air stream 58, the efficiency of the exhaust ventilation system is increased.
Air is drawn or sucked into the exhaust ventilation system by the blowers 50 and 52 through a suction grill or opening 59. The suction opening 59 is provided in the bottom closure wall 24. A filter (not shown) may be provided adjacent the suction opening 59 for filtering air as it passes into the air exhaust path 48. After the air stream 58 passes through the blowers 50 and 52, the air stream is divided between two upwardly directed rear air channels 60 and 62 defined between the rear wall 20 of the enclosure 14 and the rear wall 34 of the oven cavity 12. The two rear air channels 60 and 62 are separated by the rearwardly stepped portion 44 which approaches the rear wall 20. The distance between the rear center section 44c and the rear wall 20 may be sufficient to allow for the provision of insulation along the surface of the rear wall 20. Or alternatively, the center section 44c may approach the rear wall 20 to the point of contact. Further, the air exhaust path may utilize only one of the rear air channels.
As seen in
The enclosure 14 of the microwave 10 is effectively divided into three basic compartments, as best seen in
The first side compartment 72 is configured to contain electrical equipment chamber 80 as shown in
Mounted to the outside of the electrical equipment chamber 80 is a cooling fan or blower 94. The cooling blower 94 is operated to draw air into the first side compartment through a top, inlet vent opening area 96 and direct this cooling air stream 98 into the electrical equipment chamber 80. The cooling air stream 98 may then pass over and around the electrical components provided within the electrical equipment chamber 80 and then pass through the magnetron 90 into the oven cavity 12 or through an air channel 99 above the oven cavity 12.
It can be understood therefore, that when the exhaust blowers 50 and 52 operate, contaminated air flows through the exhaust ventilation system and is vented out into the ambient air through the center vent area 66. Since there is complete isolation of the first side compartment 72 and the electrical equipment chamber 80 from the exhaust ventilation system, the contaminated air stream 58 passing through the exhaust ventilation system does not flow through the electric equipment installation chamber 80. Therefore, the electric equipment such as the magnetron 90 and the high-voltage transformer 92, are not exposed to the contaminated air sucked through the exhaust ventilation system.
Turning now to
It can be understood that it is desirable to minimize the overall height of the enclosure (H2) while at the same time providing a desired or required internal height within the oven cavity (H1). In particular, it is desirable to accommodate the desired cavity height (H1) without having the bottom closure wall 24 and a lower front edge 122 of the bottom closure wall too close to the cooktop which may be provided below the microwave oven 10. By providing a sufficient space between the lower front edge 122 and the cooktop, visibility of the cooktop is enhanced and the bottom closure wall 24 does not become too warm. The configuration of the present invention is designed to provide the desired visibility and space between the lower front edge 122 and the cook-top. By locating the top vent area 102 along the top surface provided of the, microwave oven and by providing a bottom closure wall 24 which extends upwardly from the bend line 56 it is possible to minimized the overall height H2 and provide the benefits discussed above.
Provided along the top vent area 102 are a pair of vent filter covers 110 and 112. These vent filter covers are preferably constructed of a plastic frame 114 which supports a filter mesh interior 116. The vent filter covers 110 and 112 are removably fitted within a depressed region 117 provided about the top vent area 102 such that the vent filter covers are positioned below a top surface 118 of the microwave oven when they are properly installed. The top surface 118 may be formed as part of the top wall 22. The vent filter covers 110 and 112 are readily removed for cleaning.
The vent filter covers are designed to provide a final filter for exhausted air passing through the exhaust ventilation system and also to prevent foreign objects from passing into the upper air plenum 64 and the first and second side compartments 72 and 74. Beneath the vent filter covers 110 and 112 are louvers 120 which direct the air flow outwardly and also support the vent filter covers 110 and 112.
Accordingly, it can be understood that the present invention provides a microwave that achieves a maximization of space within the oven cavity 12. This is achieved through use of a unique exhaust ventilation system having an air exhaust path which flows air through a pair of rear air channels which are divided by the rearwardly stepped portion 44 of the oven cavity 12. In this way, the oven cavity may be sized sufficiently large to accommodate a large turn table plate 42—which may be as large as 40 centimeters to accommodate large items. Additionally, since the air exhaust path does not occupy any space along the sides the oven cavity 12, a maximum cavity width is feasible. The oven cavity width is only limited within the enclosure by the first and second side components which may be configured to contain an electrical equipment chamber 80.
It can be understood, moreover, that by locating the top vent opening along the horizontal top, front surface of the microwave oven and having the bottom closure wall slope upwardly from a bend line the desired oven cavity height may be accommodated while minimising the overall height of the microwave oven. Moreover, the attractiveness of the microwave is enhanced by locating all of the vent openings on surfaces other than the front surface which formed primarily by the pivotable door 26.
As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.
