JPH0432617A - Microwave oven - Google Patents

Abstract

PURPOSE:To provide a micrwave oven in which no dew formation is generated at a heat generating wire even if vapor enters a pipe of a heater and its durabilityis not reduced due to a formation of rust or a reduced insulation by a method wherein when an amount of vapor generated during a micro-wave heating and cooking operation is more than its specified value, this state is detected by a sensor and a heater for use in heating through oxidization catalyst is electrically energized. CONSTITUTION:During a microwave heating and cooking operation with a magnetron 5, a heater 12 of a deodoring device 13 is not electrically energized in principle, but a fan device 8 is operated, so that surrounding air passes through a duct 9 and is supplied into a cooking chamber 2 and then the surrounding air is discharged out of the chamber through a discharging duct 10. An amount of vapor contained in the air to be discharged through the discharging duct 10 is specifically varied as the microwave heating and cooking is being carried out, so that this variation of the amount of vapor is detected by a gas sensor 14. As a detected amount of vapor detected by this gas sensor 14 is more than a specified value, the control device 24 repeats an electrical energization of the heater 12 for use in heating an oxidization catalyst 11 for a predetermined period of time for every predetermined time. Accordingly, even if the vapor enters the pipe 16, no dew formation is made at a nichrome line 17.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a microwave oven equipped with a deodorizing device.

(Prior art) In oven grill ranges, it has been considered to provide a deodorizing device in the exhaust path of the cooking chamber in order to remove odors generated during heating cooking with a heater, specifically during oven cooking or grill cooking. . This deodorizing device includes an oxidation catalyst and a heater for heating and activating the oxidation catalyst. In this case, the heater used is one in which a heating wire such as a nichrome wire is provided inside a quartz pipe or a ceramic pipe, taking into account heating start-up performance, durability, and the like.

(Problems to be Solved by the Invention) During microwave cooking, a large amount of steam is generated from food. However, during microwave cooking, the heater for heating the oxidation catalyst is in a power-off state, so the steam enters the pipe and condenses on the heating wire, causing the insulation to deteriorate.
This causes problems such as rust and reduced durability. To solve this problem, a ceramic heater may be used, but this increases the cost.

If such a problem exists, the question may arise as to whether it would be better to activate the oxidation catalyst by causing the heater to generate heat during microwave cooking.

However, during oven cooking or grill cooking, the inside of the cooking chamber is heated by an oven heater or a grill heater, so high-temperature air flows through the exhaust path. For this reason, the oxidation catalyst is heated by the high temperature air, so
For oxidation catalysts, some only require supplementary heating of the oxidation catalysts. However, during microwave cooking, high-temperature air as mentioned above does not flow through the exhaust passage, so the heater for heating the oxidation catalyst must have a high output to heat the oxidation catalyst to the activation temperature. I can't. However,
In order to increase the output of the heater for heating the oxidation catalyst, the power consumption of the entire microwave oven will exceed the rated power unless the magnetron is stopped. Therefore, when the heater for heating the oxidation catalyst is energized, the magnetron must be turned off. The need arose;
As a result, cooking time becomes longer. For this reason, take into account that when cooking with microwave heating, unlike oven cooking or grill cooking, there is less heating that produces strong odors.
The oxidation catalyst is not activated, that is, the heater is not energized.

SUMMARY OF THE INVENTION An object of the present invention is to provide a microwave oven that does not cause condensation on the heating wire even if steam enters the pipe of the oxidation catalyst heating shield during microwave cooking.

[Configuration of the Invention (Means for Solving the Problems) The microwave oven of the present invention includes a heater for heating and activating an oxidation catalyst, and a heating wire disposed in a pipe,
The present invention is characterized in that when the amount of steam generated during microwave cooking exceeds a certain level, a sensor detects this and energizes a heater for heating the oxidation catalyst.

(Function) During microwave cooking, when the amount of steam generated exceeds a certain amount, the heater for heating the oxidation catalyst is energized.

Therefore, even if steam enters the pipe of the heater, there is no risk of condensation forming on the heating wire.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

First, in FIGS. 3 and 4, which schematically show the overall structure, an outer box 1 has a cooking chamber 2 inside and an inner box 3 disposed therein. A magnetron 5 is disposed in a machine room 4 formed on the right side of the inner box 3, and a fan device 8 comprising a fan 7 attached to a motor 6 is disposed. The fan device 8 is a device that sucks outside air and blows it to the magnetron 5. A part of the air that has passed through the magnetron 5 is supplied into the cooking chamber 2 through a duct 9. The air supplied into the cooking chamber 2 is discharged to the outside through an exhaust duct 10 that is an exhaust passage provided on the left side of the inner box 3. This exhaust duct 1
As shown in FIG. 1, a deodorizing device 13 consisting of an oxidation catalyst 11 and a heater 12 for heating and activating the oxidation catalyst 11, and a gas sensor 14 for detecting steam and the like are provided in the 0. Note that these are arranged in the order of gas sensor 14, heater 12, and oxidation catalyst 13 toward the direction of air flow from cooking chamber 2.

As shown in FIG. 1, the heater 12 has insulators 15 at both ends.
A nichrome wire 17 as a heat generating wire is disposed inside a pipe 16 such as a quartz pipe or a ceramic pipe sealed by a quartz pipe, and an insulator 15 of the insulator 15 is supported on both sides of the exhaust duct 10. By the way, this heater 12
is different from a sheathed heater in that a sheathed heater has a nichrome wire placed inside a metal pipe and is filled with magnesia, and both ends of the metal pipe are tightly sealed, whereas the heater 12 is simply a pipe. The pipe roller is simply arranged with a nichrome wire 17 inside it and an insulator 15 attached to both ends, and both ends of the pipe roller are not strictly sealed.

On the other hand, on the rear side of the inner box 3, as shown in FIGS. 3 and 4, a heater 18 for oven cooking is arranged.
When the circulation fan 19 is rotated by the motor 20 during oven cooking, air heated by the heater 18 is supplied into the cooking chamber 2. In addition, a heater 2 for grill cooking is provided on the top surface of the inner box 3.
The heat of this heater 21 is radiated into the cooking chamber 2.

Furthermore, a door 22 for opening and closing the cooking chamber 2 is pivotally provided on the front side of the outer box 1, and an operation panel 23 is also provided. Although not shown, the operation panel 23 is provided with various switches, indicators, and the like. Further, on the back side of the operation panel 23, a control device 24 mainly composed of a microcomputer is provided. control.

In the above configuration, during oven cooking or grill cooking performed using the oven cooking heater 18 or the grill cooking heater 21, the heater 12 of the deodorizing device 13 is energized to heat and activate the oxidation catalyst 11. For this reason,
Odor contained in the air exhausted from the cooking chamber 2 to the outside through the exhaust duct 10 is decomposed and removed by the oxidation catalyst 11.

On the other hand, during microwave heating cooking performed by the magnetron 5, the heater 12 of the deodorizing device 13 is not energized in principle, and therefore the oxidation catalyst 11 does not exhibit a deodorizing effect. By the way, since the fan device 8 is operated during microwave cooking, outside air is supplied into the cooking chamber 2 through the duct 9.
Then, it is exhausted to the outside through the exhaust duct 10. The amount of steam (steam concentration) in the air discharged through this exhaust duct 10 changes as the microwave cooking progresses, as shown in Figure 2 (
It changes as shown in a). The change in the amount of steam is detected by the gas sensor 14, and the control device 24 determines whether the amount of steam detected by the gas sensor 14 is a constant value (S in FIG. 2(a)).

), as shown in FIG.
The process of energizing the chrome wire 17) is repeated at predetermined time intervals. Note that, as shown in FIG. 2(C), the magnetron 5 is de-energized while the heater 12 is energized. Due to the energization of the heater 12, even if the amount of steam in the air passing through the exhaust duct 10 is large and the steam enters the pipe 16 through the gap between the insulator 15 and the pipe 6, dew condenses on the nichrome wire 17. There is no risk of it happening. Note that the gas sensor 24 also serves as an automatic cooking sensor that controls cooking based on the amount of steam generated.

[Effects of the Invention] As explained above, according to the present invention, when the amount of steam generated during microwave cooking exceeds a certain amount, a sensor detects this and energizes the heater for heating the oxidation catalyst. As a result, even if steam enters the heater pipe, there is no risk of condensation forming on the heating wire.
There is no risk of rust or insulation deterioration resulting in reduced durability.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is an enlarged longitudinal sectional side view of the main part, Fig. 2 is a time chart showing changes in the amount of steam generated during microwave heating, and Figs. 3 and 4. 1 is a cross-sectional plan view and a vertical cross-sectional side view of the entire microwave oven. In the figure, 5 is a magnetron, 11 is an oxidation catalyst, 12 is a heater for heating the oxidation catalyst, 13 is a deodorizing device, 14 is a gas sensor, 16 is a pipe, 17 is a nichrome wire (heating wire) 1
8 is a heater for oven cooking, and 2] is a heater for grill cooking. Applicant: Toshiba Corporation

Claims (1)

[Claims] 1. In addition to microwave heating cooking, an oxidation catalyst that can be heated with a heater and is provided with an oxidation catalyst in the exhaust passage of the cooking chamber that exhibits a deodorizing effect when activated by heating during cooking with the heater; A heater for heating and activating the oxidation catalyst is configured by arranging a heat generating wire in the pipe, and when the steam generated during microwave cooking exceeds a certain amount, a sensor detects this and activates the oxidation catalyst. A microwave oven configured to energize a heater.