Air circulation structure for microwave oven

Abstract: An air circulation structure for a microwave oven is disclosed. The structure includes a fan (31) for sucking air into the interior of a machinery compartment (23) installed below a cooking chamber (20) of the microwave oven, a bottom plate (24) having an air suction port (25) through which an air sucked by the fan and radiating heat generated from the electrical elements of the microwave oven is flown into the interior of the cooking chamber, and a rear surface plate having a first air discharge port (27) through which the air passed through an air suction port formed on the bottom plate and circulated in the interior of the cooking chamber is discharged to the outside of the microwave oven, for thereby effectively radiating heat from electrical elements of a microwave oven having a machinery chamber installed below a cooking chamber and dehumidifying from the interior of the cooking chamber.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a microwave oven, and in particular to an air circulation structure for a microwave oven which is capable of effectively radiating heat from electrical elements and dehumidifying from a cooking chamber by enabling an effective easier air circulation in a microwave oven having a machinery compartment below the cooking chamber. 2. Description of the Conventional Art Generally, the microwave oven is directed to cooking foods using microwaves generated by a microwave generation source and is formed of a door, a cooking chamber in which foods are cooked, and a machinery compartment having various elements therein. In the thusly constituted microwave oven, an air circulation structure is formed for quickly radiating heat from a magnetron and a high voltage transformer installed in the machinery compartment and externally introducing air into the interior of the microwave oven for discharging a high temperature vapor generated in the interior of the cooking chamber during a cooking operation to the outside. As shown in Figures 1 and 2, in the conventional air circulation structure for a microwave oven, a suction guide member 7 sucking air from the outside of the microwave oven is formed on an inner surface of a back plate 4, and a fan 6 sucking air from the outside of the microwave oven is installed at the suction guide member 7. The fan 6 generating a predetermined suction force for sucking air from the outside of the microwave oven is driven by a fan motor 6M. In addition, in the machinery compartment 11 formed on an outer lateral surface of a cavity 1, an air duct 8 is installed for guiding the external air cooling the magnetron 9 into the interior of the cooking chamber 3. In the drawings, reference numeral 2 represents a door, 5 represents an air suction port, and 10 represents a high voltage transformer. The air circulation by the air circulation structure for a conventional microwave oven will be explained with reference to the accompanying drawings. In the air circulation structure for a conventional microwave oven, when the fan motor 6M is driven for thereby rotating the fan 6 and then generating a predetermined suction force, air is introduced into the interior of the microwave oven through the air suction port 5 formed in the back plate 4. The air introduced into the interior of the microwave oven is guided by the suction guide member 7 formed on the inner surface of the back plate 4 and is flown to the magnetron 9 and the high voltage transformer 10 for thereby cooling the magnetron 9 and the high voltage transformer 10, and then is flown into the interior of the cooking chamber 3 through the air duct 8. The air flown into the interior of the cooking chamber 3 is discharged, together with the vapor in the cooking chamber 3, to the outside of the cooking chamber 3 for thereby removing vapor from the cooking chamber 3. However, since the air circulation structure for the conventional microwave oven includes a machinery compartment provided on a lateral surface of the microwave oven, the conventional air circulation structure is not applicable for the microwave oven formed in various structures. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an air circulation structure for a microwave oven which overcomes the aforementioned problems encountered in the conventional art. It is another object of the present invention to provide an air circulation structure for a microwave oven which is capable of effectively radiating heat from electrical elements of a microwave oven having a machinery chamber installed below a cooking chamber and dehumidifying from the interior of the cooking chamber. To achieve the above objects, there is provided a microwave oven of the type known from JP 61 186722 A, WO 86 02143 A and DE 36 08 432 A, including a machinery compartment, a cooking chamber and a microwave oven door, according to claim 1. Advantageously, the microwave oven of the invention further comprises the features of dependent claims 2-6. Additional advantages, objects and features of the invention will become more apparent from the description which follows. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: Figure 1 is a perspective view illustrating an inner structure of a conventional microwave oven in which a machinery compartment is installed at a lateral surface of a cooking chamber; Figure 2 is a view illustrating an air flow by an air circulation structure for a conventional microwave oven; Figure 3 is a side cross-sectional view illustrating an air circulation structure for a microwave oven according to the present invention; and Figure 4 is a plan cross-sectional view illustrating an air circulation structure for a microwave oven according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be explained with reference to the accompanying drawings. In the air circulation structure for a microwave oven according to the present invention, as shown in Figures 3 and 4, there are provided a fan 31 and a fan motor 30 for driving the fan 31 inside a base plate 28. A microwave guide member 33 is formed below a bottom plate 24 of a cooking chamber 20. In addition, a magnetron 35 is installed on a lateral surface of the wave guide member 33 for generating microwaves, with its lateral surface being opposite to the fan 31. As shown in Figures 3 and 4, a suction port 25 is formed at an end portion of the bottom plate 24 forming the bottom of the cooking chamber 20 for flowing the air sucked by the fan 31 into the cooking chamber 20 therethrough. The suction port 25 is formed near the door 21 for preventing dew from being condensed on the inner surfaces of the door and effectively circulating air inside the cooking chamber 20. In addition, a first air discharge port 27 is formed at an upper portion of the rear plate forming the rear surface of the cooking chamber 20 for flowing the air circulated inside the cooking chamber 20 to the outside therethrough for thereby effectively circulating the air of a high temperature in the cooking chamber 20. A discharge guide member 40 is formed on an outer portion of the rear plate, in which the first air discharge port 27 is formed, for thereby guiding a discharge of the air through the first air discharge port 27. The discharge guide member 40 is directed to effectively discharging the air even when the microwave oven is installed near the wall of a house or a building by obtaining enough space between the wall and the rear surface of the microwave oven for thereby implementing an effective external suction of air. In addition, a second air discharge port 29 is formed on the base plate 28 forming the bottom surface of the machinery compartment 23 for discharging the air heated while passing through the magnetron to the outside. In the drawings, reference numeral 26 represents a rear surface plate, and 45 represents a tray. The circulation of the air based on an air circulation structure according to the present invention will be explained with reference to the accompanying drawings. Namely, in the air circulation structure for a microwave oven according to the present invention, when electric power is supplied to the microwave oven, the cooking operation is started in the cooking chamber 20, and the fan motor 30 is driven, and the fan 31 is rotated. Therefore, air is forcibly introduced from the outside of the microwave oven into the machinery compartment 23 by the rotation force of the fan 31, and the thusly introduced air passes trough the magnetron 35, the high voltage transformer, etc. for thereby radiating heat therefrom. A part of the air passed through the magnetron 35 and the high voltage transformer is discharged to the outside of the microwave oven through the second air discharge port 29 formed on the base plate 28 forming the bottom surface of the machinery compartment 23, and the remaining air is flown into the interior of the cooking chamber 20 through the suction port 25 formed at the end portion of the bottom plate 24 forming the bottom surface of the cooking chamber 20. The air flown into the cooking chamber 20 circulates inside the cooking chamber 20 and sucks vapor in the interior of the cooking chamber 20. At this time, the air flown into the interior of the cooking chamber 20 is heated by a high temperature air in the interior of the cooking chamber 20 and is flown from the lower portion to the upper portion inside the cooking chamber and then is discharged through the first air discharge port 27 formed on the upper end portion of the rear surface plate forming the rear surface of the cooking chamber 20 and is discharged to the outside of the microwave oven by the guide of the discharge guide member 40. In addition, since the suction port 25 is formed at an end portion of the bottom plate 24 of the cooking chamber 20, when air is externally introduced thereinto through the suction port 25, a part of the thusly introduced air is upwardly flown along the inner surface of the door 21. Here, the above-described flow of the air may help removing the vapor moving along the inner surface of the door 21 for thereby preventing a dew condensation on the inner surface of the door 21. As described above, in a microwave oven having a machinery compartment below the cooking chamber, it is possible to more effectively suck air into the interior of the microwave oven for thereby enhancing a radiating operation of high temperature air generated from the parts such as a magnetron, etc. compared to the conventional art. In addition, in the present invention, it is possible to prevent a dew condensation on the inner surface of the door by installing a suction port at the upper portion of the cooking chamber, so that the vapor in the interior of the cooking chamber is effectively removed by the air flown into the cooking chamber. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the invention as recited in the accompanying claims.

Claims: A microwave oven including a machinery compartment (23), a cooking chamber (20) and a microwave oven door (21) characterized in that it comprises: a fan (31) for providing air into the interior of the machinery compartment (23) installed below the cooking chamber (20): a bottom plate (24) having at least one air inlet port (25) through which the air from the fan (31) and radiating heat generated from electrical elements of the microwave oven is provided into the cooking chamber (20) and provided adjacent to the door (21); and a rear surface plate (26) having a first air discharge port (27) through which the air in the cooking chamber (20) is discharged from the microwave oven. The structure of claim 1, wherein said air inlet port (25) is formed at an end portion of the bottom plate (24) and said first air discharge port (27) is formed at an upper portion of the rear surface for thereby implementing a natural circulation of air in the interior of the cooking chamber (20). The structure of claim 1 or 2, wherein a discharge guide member (40) is formed at a portion corresponding to the first air discharge port (27) for guiding the air discharged from the cooking chamber (20) to the outside of the microwave oven. The structure of either one of claims 1 to 3, wherein a second air discharge port (29) is formed on a lower surface of the machinery compartment (23) installed below the cooking chamber (20) for discharging the air radiating the heat from the electrical elements to the outside of the microwave oven therethrough. The microwave oven of claim 1, wherein the fan (31) is located within the machine compartment (23). The microwave oven of claim 1, wherein the bottom plate (24) has two or more inlet ports (25) formed along an edge portion adjacent to the opening of the cooking chamber (20).

Inventors: KANG JONG-SOO, SEO DONG-WAN, KANG, JONG-SOO, SEO, DONG-WAN
Applicants: LG ELECTRONICS INC, LG ELECTRONICS INC.
Application year: 1998
Main classification: H05B6
IPC codes: H05B6