JP2823391B2 - Heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating apparatus, such as a microwave oven, for controlling heating by detecting information on the atmosphere in a heating chamber flowing in an exhaust duct with a sensor.

[0002]

2. Description of the Related Art Recently, a microwave oven using a sensor for detecting absolute humidity in a heating chamber and performing microwave heating or heater heating based on the output of the sensor has been put into practical use (Japanese Patent Publication No. 2-46101). ). Specifically, the sensor is fixed to a discharge duct that discharges the atmosphere in the heating chamber, and detects the absolute humidity that is information on the atmosphere in the heating chamber flowing in the discharge duct.

However, in such a configuration,
High heat due to heating is transmitted from the heating chamber side to the sensor via the discharge duct, and the detection accuracy of the sensor decreases.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a configuration in which information on the atmosphere in a heating chamber flowing through an exhaust duct is detected by a sensor fixed to the duct. It is an object of the present invention to provide a heating device capable of preventing the temperature from being lowered due to the heat, and capable of correctly controlling the heating based on the sensor output.

[0005]

A heating apparatus according to the present invention comprises a heating chamber for storing an object to be heated, heating means for heating the object to be heated in the heating chamber, and a heating chamber connected to the wall of the heating chamber. A discharge duct that discharges the atmosphere of the discharge duct, and a sensor that detects information on the atmosphere flowing through the discharge duct and outputs a signal for controlling the heating unit. An opening for inserting the sensor, and a convex portion for fixing the flange portion of the sensor in order to fix the sensor in a state inserted into the opening near the opening,
Further, a configuration in which a heat insulating sealing material arranged on the wall of the discharge duct is extended and interposed at a space between the flange of the sensor and the peripheral edge of the opening of the discharge duct formed when the sensor is fixed to the convex portion. It is. Further, there is provided mitigation means mounted in the discharge duct to reduce the flow of the atmosphere to the sensor.

[0006]

[Function] The sensor is mounted by fixing the flange to the partially convex part of the discharge duct. High heat accompanying heating is transmitted from the heating chamber side to the discharge duct, but hardly transmitted to the above sensor, and the detection accuracy of the sensor Does not decrease under the influence of high heat.

Further, when the flange portion of the sensor is fixed to the partially convex portion as described above, the flange portion is formed on the discharge duct so that the sensor enters the discharge duct when the sensor is mounted, except for the convex portion. Away from the edge of the opening. Then, as it is, the atmosphere in the heating chamber flowing in the discharge duct,
Leakage from the separation duct through the opening to the outside of the discharge duct makes it impossible for the sensor to correctly detect atmosphere information. However, the space above is covered with a heat-insulating sealing material,
The atmosphere is prevented from leaking out of the discharge duct, and the sensor detects correct atmosphere information.

Further, in the discharge duct, the flow of the atmosphere to the sensor is reduced by the mitigation means, and in this respect, the detection accuracy of the sensor is also prevented from lowering.

[0009]

1 to 3 show the overall structure of a microwave oven according to an embodiment of the present invention. A heating chamber 1 for storing food is provided in a microwave oven main body. The food in the heating chamber is microwave-heated by microwaves from a magnetron 2 as a heating means, and a halogen heater 3 as another heating means. Is heated by the heater. Halogen heater 3
Is located above the upper wall 4 of the heating chamber,
A large number of punching holes are formed directly below the heater, and heater heat is supplied from the punching holes into the heating chamber to heat the food. The upper half of the halogen heater 3 is covered with a metal reflector 5 for efficiently supplying the heater heat into the heating chamber. Furthermore,
A cooling fan 6 for cooling the magnetron 2 is provided, and the cooling air after the magnetron cooling is supplied into the heating chamber 1 and reaches the reflecting plate 5 with the atmosphere in the heating chamber, and the upper wall of the heating chamber is cooled. The light is discharged to the outside through a metal discharge duct 7 connected to the light source 4 via a reflection plate 5.

Referring back to FIGS. 4 and 5, reference numeral 21 denotes a heat-insulating sealing member for insulating heat transmitted to the outside from the discharge duct 7 disposed above the upper wall 8 of the discharge duct 7. In the structure in which the absolute humidity sensor 11 is fixed to the partial protrusion 10 via the flange 12, except for the protrusion 10, the flange 12 is connected to the discharge duct 7 when the sensor 11 is mounted. Peripheral portion 2 of opening 9 formed in discharge duct 7 so as to enter inside
Move away from zero. Then, in this state, the discharge duct 7
The atmosphere inside the heating chamber flowing inside leaks out of the discharge duct through the opening 9 from the separated location, and the sensor 11 cannot correctly detect the atmosphere information. In view of this, the collar 12
By extending and interposing the heat insulating sealing material 21 between the opening peripheral edge 20 and the opening portion, the above-mentioned separated portion is covered with the heat insulating sealing material 21, and the leakage of the atmosphere to the outside of the discharge duct 7 is suppressed. 11 detects the correct absolute humidity.

This will be described in more detail with reference to FIG. 6 showing an absolute humidity output circuit including the absolute humidity sensor 11. The absolute humidity sensor 11 includes open and closed type temperature detecting thermistors 14 and 15 having the same temperature characteristics.
5 and a first and second resistor 16,
It comprises a bridge circuit 18 in which serial circuits 17 connected in series are connected in parallel, and an amplifier 19 which inputs a level difference between the midpoints of both series circuits and outputs an absolute humidity. Winter season
At this time, the thermistor is self-heated to about 200 ° C.
In this absolute humidity output circuit, if the atmosphere flowing through the discharge duct 7 does not contain water vapor, the thermistors 14 and 15 of the absolute humidity sensor 11 only change evenly based on the ambient temperature. Bridge circuit 1
No level difference occurs between the midpoints of the two series circuits of FIG.
The absolute humidity output of 9 is 0. On the other hand, when the food is heated and water vapor is generated from the food, and this water vapor is contained in the atmosphere flowing through the discharge duct 7, each thermistor 14,
Among them, the closed thermistor 15 is not affected by water vapor, but the open thermistor 14 has a resistance value that changes due to heat of vaporization when water droplets of water vapor adhere to the surface and the water droplets evaporate again. In this case, a level difference occurs between the middle points of the two series circuits of the bridge circuit 18, and the amplifier 19 outputs an absolute humidity corresponding to the water vapor.

In consideration of such an absolute humidity output circuit, although the thermistors 14 and 15 are selected to have the same temperature characteristics, it is assumed that the thermistors 14 and 15 have completely the same temperature characteristics. No, each thermistor 1
There are some differences in the thermal response speeds and temperature coefficients of 4 and 15.
Then, even if high heat is transmitted to the absolute humidity sensor 11, a considerable level difference occurs between the center points of the two series circuits of the bridge circuit 18, which causes a decrease in sensor detection accuracy due to the influence of the high heat. However, if the structure is such that high heat is hardly transmitted to the absolute humidity sensor 11 as described above, the sensor 11 is not much affected by the high heat and the sensor detection accuracy does not decrease.

Returning to FIGS. 4 and 5, in the structure in which the absolute humidity sensor 11 is fixed to the partial convex portion 10 via the flange portion 12, the flange portion 12 except for the convex portion 10 The peripheral portion 2 of the opening 9 formed in the discharge duct 7 so that the sensor 11 enters the discharge duct 7 when the sensor 11 is mounted.
Move away from zero. Then, in this state, the discharge duct 7
The atmosphere inside the heating chamber flowing inside leaks out of the discharge duct through the opening 9 from the separated location, and the sensor 11 cannot correctly detect the atmosphere information. In view of this, the collar 12
A heat insulating seal material 21 is interposed between the heat insulating seal material 21 and the opening peripheral edge portion 20, and the above-mentioned separated portion is covered with the heat insulating seal material 21 to suppress the atmosphere from leaking out of the discharge duct 7.
1 detects the correct absolute humidity.

Further, in the discharge duct 7, a ring-shaped relaxation member 22 which is located around the absolute humidity sensor 11 and reduces the flow of the atmosphere to the sensor 11 is fixed to the discharge duct 7 by welding. With this relaxation body 22,
The fast flowing atmosphere does not hit the sensor 11 locally, and the atmosphere relaxed by the relaxation body 22 reaches the sensor 11 from the opening 23 of the relaxation body 22. In this regard, the detection accuracy of the sensor 11 also decreases. Is suppressed. If the atmosphere locally hits the sensor 11, a level difference occurs between the middle points of the two series circuits of the bridge circuit 18, and the detection accuracy of the sensor 11 is reduced.

[0015]

According to the present invention, in a configuration in which information on the atmosphere in a heating chamber flowing through an exhaust duct is detected by a sensor fixed to the duct, the detection accuracy of the sensor is affected by high heat accompanying heating. Thus, it is possible to provide a heating device capable of suppressing a decrease in the temperature and allowing the sensor to detect correct atmosphere information, and capable of controlling heating correctly based on the sensor output.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view of the microwave oven.

FIG. 3 is a plan sectional view of the microwave oven.

FIG. 4 is a sectional view of a main part of the microwave oven.

FIG. 5 is a plan view of a main part of the microwave oven.

FIG. 6 is an absolute humidity output circuit diagram of the microwave oven.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Magnetron 3 Halogen heater 7 Discharge duct 9 Opening 10 Convex part 11 Absolute humidity sensor 12 Flange part 21 Insulation seal material 22 Relaxation body

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F24C 7/02 325

Claims (2)

(57) [Claims] 1. A heating chamber for storing an object to be heated, heating means for heating the object to be heated in the heating chamber, a discharge duct connected to a wall of the heating chamber and discharging an atmosphere in the heating chamber;
A sensor for detecting information on the atmosphere flowing in the discharge duct and outputting a signal for controlling the heating means; and an opening for inserting the sensor in a wall of the discharge duct; A convex portion for fixing the flange portion of the sensor for fixing the sensor in a state of being inserted into the opening; and a flange portion of the sensor and a discharge portion formed when the sensor is fixed to the convex portion. A heating device, characterized in that a heat insulating seal material disposed on a wall of the discharge duct extends and intervenes at a location separated from an opening peripheral portion of the duct. 2. The heating device according to claim 1, further comprising a mitigation means mounted in the discharge duct to reduce a flow of an atmosphere to the sensor.