JPH0743233U - Microwave oven with a closable kitchen - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents the equipment from being damaged by steam generated in the cooking chamber in all operating states in a microwave oven with various heating systems, especially microwave operation and grill operation. To do. The adjuster is adjustable to at least two open positions to allow ventilation, and a first of these open positions.
The open position of the second position belongs to the high frequency operation, and the second open position of the second position belongs to the grill operation.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention comprises a closable cooking chamber in which a grill heating element is arranged and a high frequency heating device and possibly another heating element such as an upper heating element and / or a lower heating element. A cooling fan, which is additionally provided and is preferably subordinate to the high-frequency heating element, is provided, through which an air flow flows through the cooking chamber, and the ventilation volume can be controlled by the adjuster in relation to the operating method of the oven range. Regarding a microwave oven.

[0002]

[Prior art]

 In the well-known microwave oven (see German Patent Application DE-A-3144493), a high-frequency generator is provided outside the cooking chamber, and the high-frequency generator is coupled to the cooking chamber via a director. There is. The high-frequency generator is equipped with a fan to cool it. At that time, a part of the cooling air used for cooling the high-frequency generator is introduced into the cooking chamber and the high-frequency generator is cooled in the cooking chamber. During operation, the strong ventilation of the cooking chamber ensures that the moisture generated from the cooked food during the heating process does not condense inside the cooking chamber, especially on the front glass plate of the cooking chamber door. In this case, the cooling air system at the entrance of the cooking chamber can be closed to the cooking chamber, depending on the operating mode. Ventilation in the cooking chamber is also planned to be performed during the combined operation of high frequency energy and heat energy.

[0004]

[Problems to be solved by the device]

 This invention aims to prevent the equipment from being damaged by steam generated in the cooking chamber under all operating conditions in an oven range with various heating systems, especially microwave operation and grill operation. And

[0005]

[Means for Solving the Problems]

 For this purpose, according to the invention, the adjusting device can be adjusted to at least two open positions which allow ventilation, of which the first of the open positions belongs to high-frequency operation in a manner known per se. , The second open position is achieved by belonging to the grill operation. Advantageous embodiments of the invention are described in claims 2 and below.

It is disadvantageous to dissipate the heat generated inside the oven to the outside by forced ventilation during the operation of the oven provided with a usual heat source such as an upper heating element or a lower heating element or a grill heating element. That was the starting point for conventional thinking. It was also found that the ventilation in the cooking chamber does not harm the grilling results with regard to the quality and time required for grilling, at least when the grill is operating. This is because heat transfer from the heat source is mainly performed by heat radiation. Based on this knowledge, the present invention ventilates the cooking chamber during the normal operation of the microwave oven and at least during the operation of the grill, which causes a large amount of damp steam, especially during grilling. The air is carried away by the ventilation to prevent condensation in the cooking chamber, for example, on the cooking chamber door or on the packing surrounding the cooking chamber door. For this purpose, according to the invention, an adjusting device, for example a ventilation door, can be adjusted in at least two open positions.

In the case of the microwave oven of the type mentioned above, when the steam discharge groove inside the equipment starts from the fan and is introduced into the outflow groove leading directly to the outside of the equipment, where cooling air and wet steam are mixed. In particular, it is advantageous according to the invention to slightly open the adjusting device to maintain some ventilation or positive pressure in the ventilation channels leading from the fan to the cooking chamber during oven operation. As a result, the positive pressure formed in the cooking chamber prevents steam from entering the ventilation groove and reaching the switch chamber from there. Such positive pressure in the cooking chamber can be generated by the positive pressure on the discharge side of the fan, and this positive pressure spreads over the steam outflow groove and into the cooking chamber.

[0008]

【Example】

 Next, the present invention will be described in detail with reference to a partial sectional view showing an embodiment of the microwave oven based on the present invention.

The drawings show the parts of the microwave oven according to this invention which are important for an understanding of this invention.

A cooking chamber 2 is provided inside the case 1, and the cooking chamber can be closed by, for example, a hinged processing chamber door 3. A chamber 4 is provided above the cooking chamber 2, and a high-frequency generator for microwave operation, a ventilation device described later, and a microwave oven control device equipped with a heating element are housed in the chamber 4. The high-frequency generator is arranged in this chamber 4 and is connected to the cooking chamber 2 via a waveguide, which is also known per se and which is also not shown in the figure.

The microwave oven further comprises an electrical resistance heating element, for example a grill heating element 5. A cooling fan 7 is used for cooling the magnetron shown in the figure or its transformer or its transformer, to which a draft air guide 8 is connected, starting from this air guide and directly There are arranged exhaust grooves 9 and 10 that open to the outside and a ventilation groove 11 that directly flows into the cooking chamber 2 and obliquely goes directly to the cooking door 3.

A ventilation valve 12 is provided in the range of the bifurcated portion of the air guide portion, and the ventilation valve is tiltable about a rotary shaft 13. This vent valve 12 is connected to one leg 14 ′ of a return spring 14 which is designed as a torsion spring, the other leg 14 ″ of which is fixedly supported. This return spring shows the vent valve 12 in broken lines. From the closed position to the open position indicated by the solid line, in which the vent valve abuts a stopper (not shown).

In the open position shown, both ventilation channels 9 and 11 are open, the air flow exiting from the cooling fan 7 is split and only a part thereof flows into the ventilation groove 11 and into the cooking chamber 2.

The ventilation valve 12 has a concentric protrusion 15 on its pivot shaft 13, and this protrusion is of a two-arm swingably supported at 17 via a spring 16 as a connecting member. It is connected to a rocking lever 18, to which the other end of a spring 16 is fixed, on the one hand the rocking lever on the other hand has a fork-shaped support 19 for a pull rod 20. . Parts 18 and 20 are components of the lever transmission mechanism.

This lever transmission mechanism is mechanically coupled directly to the control disc 21, which is rigidly coupled to a selection switch, not shown, which is designed as a rotary knob of the microwave oven. Various operating methods such as "microwave operation", "grill operation" and "oven operation" can be set using the switch.

An air outlet hole 22 provided with an outflow groove 23 is provided on the rear side of the ceiling portion of the cooking chamber 2, and this outflow groove is an outflow for cooling air that directly flows out of the appliance as shown by a broken line. It flows into the grooves 9 and 10.

In pure microwave operation, in which only the high-frequency generator is turned on, the control device in the form of the ventilation valve 12 is designed to completely open the ventilation cross-section of the ventilation groove 11, so that cooking A relatively strong air flow is generated in the chamber 2. At this time, this ventilation removes the steam generated from the cooked food. Condensation on the cooking chamber wall, in particular on the inside of the cooking chamber door, is prevented and is carried away through the air outlet hole 22, the outflow groove 23 and the outflow groove 9/10.

The vent valve 12 is also in the open position during the combined operation using the high frequency heating and the normal resistance heating.

In addition, during the pure grill operation and accordingly when only the grill heating element 5 is turned on, the above-mentioned lever transmission mechanism is used by a corresponding twist of the selection switch, that is, by selecting the operation method “grill”. The vent valve 12 is moved to an open position that closes the ventilation cross-sectional area up to about 30% with reference to the completely open position during high frequency operation.

Here, the steam generated during the grill operation is similarly carried out by the air flow, and at this time, the hot steam and the cooling air sent from the fan are mixed in the outflow groove 9. The mixed air then has only a relatively low temperature at the outlet.

In the "oven" operating position, the vent valve 12 is also in the open position, preferably in the open position such that the vent valve closes the cross-sectional area of the ventilation by more than 90%. Thus, even in this operation method, weak ventilation is generated in the ventilation groove 11 and a slight positive pressure is generated. Due to this positive pressure, steam generated during oven cooking enters the ventilation groove 11 and reaches the chamber 4. Is prevented.

Such positive pressure is required when the air outlet hole 22 for steam is directly connected to the outflow groove 9/10 as shown in the figure. If this positive pressure does not exist, the positive pressure generated in the outflow groove 9 by the cooling fan 7 is transmitted to the cooking chamber 2 through the outflow groove, thereby pushing steam into the ventilation groove 11. As will be the case, this is prevented by this invention.

The open position of the vent valve 12, which is dependent on the various operating positions of the selector switch, corresponds to a control disk 21 similar to that shown in FIG. 2 of DE-A-3337147. It can be easily realized with an appropriate shape.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of a microwave oven according to the present invention.

[Explanation of symbols]

 2 Cooking room 5 Grill heating element 6 High frequency generator 7 Cooling fan 9, 10 Outflow groove 11 Ventilation groove 12 Adjuster (vent valve) 22 Air outlet hole

Front page continuation (72) Inventor Werner, Schüner Bell Federal Republic of Traunreut, Berliner Schyutraße 3 (72) Inventor Herbert, Schyutainer German Traunschütstein, Kaiser Schutlerse 1

Claims (5)

[Scope of utility model registration request] 1. A heating element having a closable cooking chamber, in which a grill heating element is arranged, and a heating element and optionally another heating element such as an upper heating element and / or a lower heating element. Further preferably, a cooling fan subordinate to the high-frequency generator is provided, and an air flow from this fan flows through the cooking chamber, and the ventilation volume can be controlled by the adjusting device in relation to the operation method of the microwave oven. In one microwave oven, the adjuster (12) is adjustable to at least two open positions to allow ventilation, the first of these open positions belonging to high frequency operation in a manner known per se, A microwave oven with a closable cooking chamber, characterized in that the second open position belongs to the grill operation. 2. A microwave oven according to claim 1, characterized in that the adjusting device (12) is adjustable to a third open position belonging to oven operation. 3. The adjusting device (12) at least almost completely opens the ventilation cross section in the open position for high frequency operation,
Ventilation cross-section is approximately 30% in the open position for grill operation
Microwave oven according to claim 1 or 2, characterized in that the ventilation cross section is closed to more than 90%, preferably more than 95% in the open position for oven operation. 4. The cooking chamber (2) has an air inlet hole and an air outlet hole (22) with a pre-connected ventilation groove (11) and an adjuster (12), which air outlet hole is provided. 2. The cooling fan (7), which separates and flows directly into the outflow groove (9/10) opening to the outside of the device.
The microwave oven according to any one of 1 to 3. 5. The adjuster (12), which is preferably a ventilation door arranged at the entrance of the ventilation groove (11) which starts from the cooling fan (7) and flows into the cooking chamber (2), has various operating modes. The microwave oven according to any one of claims 1 to 4, which is combined with a selection switch used for selection and can be operated by the selection switch.