JPH0211821B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooking device such as a microwave oven that is equipped with microwave heating means and external heating means, and particularly relates to a cooking device that non-contactly measures the temperature of food to be cooked. The present invention relates to an improvement in a cooking device equipped with a device for cooking.

[Prior art]

Cooking appliances have been developed that are equipped with devices that non-contactly measure the temperature of the food being cooked in order to monitor the thawing state, cooking progress, etc. and adjust the heating power.
This temperature measurement is carried out by capturing the infrared rays emitted by the food using an infrared detection element and using the output thereof (for example, Japanese Patent Application Laid-Open No. 105352/1983). In addition to the microwave heating means, in a microwave oven or the like which is equipped with a means for heating food from the outside, such as a heater or gas burner, when this external heating means is driven, the temperature inside and outside the cooking chamber becomes considerably high. Temperature measurement devices use electronic components, and some of them must be installed in areas that are affected by the high temperature atmosphere of the cooking room, so we need to ensure that they can operate stably over a long period of time. Cooling is necessary. In view of the fact that the temperature of the food to be cooked rises even after the heating means has been driven, it is desirable to cool the food for a while not only while the heating means is being driven, but also after it has been driven.

Japanese Utility Model Application Publication No. 50-48241 discloses an apparatus in which a cooling fan is driven even after the heating means is driven in a microwave oven. This device is equipped with a temperature switch, and when this switch reaches a predetermined temperature or higher, it closes and drives the cooling fan. This type of control may be used for devices such as this one, which are not equipped with a food temperature measuring device and are equipped with a fan for the purpose of preventing abnormal temperature rises in various parts of the cooker, but a non-contact type temperature measuring device may be used. If equipped with such a device, it is necessary to perform post-cooling after driving the heating means to protect the temperature measuring device, which is sensitive to heat.

[Problem that the invention seeks to solve]

Conventionally, the cooling fan was driven for a certain period of time after the cooking device was heated, but in some cases this resulted in unnecessary cooling and increased power consumption.

The present invention has been made in view of the above circumstances. When the temperature measuring device reaches a high temperature such as when the external heating means is driven, it is possible to cool the temperature measuring device for a relatively long time after heating, and also to cool the temperature measuring device for a relatively long time when the external heating means is driven. To provide a cooking device that protects a temperature measuring device and saves power reasonably by cooling the temperature measuring device for a relatively short period of time after heating when the temperature measuring device does not reach a very high temperature as sometimes happens. .

[Means for solving problems]

The cooking device according to the present invention includes a microwave heating means and an external heating means for heating the food to be cooked, a temperature measuring device for non-contactly measuring the temperature of the food, and a fan for cooling the temperature measuring device. In the cooking device, the cooking device includes a control unit that controls the driving of the heating means based on the temperature measured by the temperature measuring device and drives the fan when the heating means is driven, in the case of driving the external heating means. means for setting a cooling time; means for setting a second post-cooling time (second post-cooling time < first post-cooling time) in the case of driving the microwave heating means; and a means for setting a second post-cooling time (second post-cooling time < first post-cooling time); and a post-cooling means for driving the fan for a first or second post-cooling time set depending on the heating means.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a schematic front sectional view of a microwave oven according to the present invention. Microwaves emitted from a magnetron 18, which is a microwave heating means arranged on the right side of the cooking chamber 14, are transmitted to the cooking chamber 1 through a waveguide 19.
4 and dielectrically heats the food 17 to be cooked placed on the rotating saucer 15. A heater storage case 11 covered with a heat insulating material 16 is provided at the upper left side of the cooking chamber 14, and a heater 12 serving as an external heating means is disposed inside the case 11, and a fan 51 (see FIG. 2) As the heater 12 rotates, the heat from the heater 12 is guided from the outlet formed in the case 11 to the cooking chamber 14 to heat the food. Above the cooking chamber 14 is a temperature measuring device 20 that non-contactly measures the surface temperature of the food 17.
Some of them are provided. That is, a hole 13 is formed in the top surface above the center of the rotary saucer 15, through which infrared rays emitted by the food are taken in. In the aforementioned hole 13, a pipe 22 for preventing microwaves from entering the sensor box 21 of the temperature measuring device 20 is installed vertically and concentrically with the hole 13, and both the hole 13 and the pipe 22 A pyroelectric infrared sensing element 2 is placed on the upper extension of the axis of the
3 is installed. This detection element 23 is housed in a shield case 24 in order to block external noise, and its output is drawn out to the outside of the shield case 24 via a feedthrough capacitor 25, and is connected to an AC amplifier 41 (see FIG. 2) which will be described later. It is arranged so that it can be given to A shutter 26 opens and closes the upper opening of the pipe 22, and is driven by an electromagnetic actuator 27.
When temperature measurement is not being performed, the shutter 26 is closed to prevent the detection element 23 from being contaminated.

The infrared rays emitted from the food 17 reach the detection element 23 through the hole 13, the pipe 22, and a small hole 24a formed in the lower wall of the shield case 24. A disk 28a of the chiyotsupa 28 is interposed between them,
The infrared rays are arranged to reach the detection element 23 intermittently. That is, the tipper 28 includes a disk 28a in which portions that transmit infrared rays and portions that block infrared rays are alternately arranged;
It consists of a motor 28b that rotationally drives this, and a photo interrupter 28c placed between the disc 28a to obtain a synchronization signal.
(See Figure 2). A diode 29 is provided slightly above the rotational range of the disk 28a to detect a temperature corresponding to the surface temperature of the disk 28a, and its output is fed to an adder 46 (see FIG. 2), which will be described later. It is set as. Sensor box 21 containing the above parts
Cooling air is blown into the interior through a duct 30 by rotation of a fan 31 (see FIG. 2) to cool them.

FIG. 2 is a schematic block diagram schematically showing the main parts of the electric circuit of the product of the present invention. The output of the infrared detection element 23 becomes an AC waveform due to the action of the chopper 28, but this output is amplified by an AC amplifier 41, unnecessary components are removed by a bandpass filter 42, and the output of the photointerrupter 28c is used. The signal is synchronously rectified by a synchronous rectifier circuit 43, then integrated by an integrating circuit 44, and the integrated output is input to an operational amplifier circuit 45. On the other hand, the output of the diode 29 is input to a temperature measurement circuit 47 using an operational amplifier circuit or the like. The output of the operational amplifier circuit 45 represents the difference between the surface temperature of the food 17 and the temperature on the upper surface of the infrared ray blocking portion of the disk 28a of the chopper 28, and the output of the temperature measurement circuit 47 based on the output of the diode 29 is The contents indicate a temperature close to the temperature of the infrared ray blocking portion of the disk 28a of the chopper 28. The output of this temperature measurement circuit 47 is inputted to an adder 46 along with the output of the operational amplifier circuit 45, and the sum of the two, that is, data representing the surface temperature of the food, is inputted to a microcomputer 48 which is the control center of the product of the present invention. It is structured as follows. Note that the circuits including the AC amplifier circuit 41 and the temperature measurement circuit 47 are provided in a portion on the right side of the cooking chamber that is not related to temperature rise in the cooking chamber.

The microcomputer 48 controls the output of the magnetron 18 and the heater 12 according to the input from the keyboard switch 49 or the food temperature input from the adder 46, and also issues a control signal to the fan drive control circuit 32 as described later. drive of the fan 31 is controlled.

In FIG. 2, 52 is a power supply circuit for exciting the magnetron 18, and a bidirectional thyristor 53 is connected to the primary side of the step-up transformer 52a, and its conduction phase angle is controlled by the microcomputer 48 to control the magnetron output. controlled. On the other hand, the output of the heater is controlled by turning on and off the relay switch 54 by the microcomputer 48. In addition, in FIG. 2, 55 is a motor for driving the saucer 15, 56 is an internal lamp, and 57 is a power/weak switch for the fan 51, which is connected to the output interface of the microcomputer 48.

Now, fan 3 by microcomputer 48
Control No. 1 will be explained. Relay switch 54
The output port 48a connected to the fan drive control circuit 32 is kept in a high state during a heating operation by closing the heater 12 and conducting a heating operation by energizing the heater 12, or during a microwave heating operation in which the bidirectional thyristor 53 is turned on and the magnetron 18 is excited. Juan 31 as level
drive the rotation.

After heating by the heater 12 or magnetron 18 is completed, cooling control is performed as shown in the flowchart of FIG. That is, it is checked whether the previous operation was heater heating (), and if it was heater heating, a time limit of the first post-cooling time T ₁ (for example, 10 minutes) is set in the timer in the microcomputer 48 ( ), the output port 48a is set to high level and the fan 31 is driven to rotate (). Then, the timer counts down (), and when the remaining time reaches 0 (), the output port 48
Set a to low level to stop the fan (). On the other hand, in the case of microwave heating, the second post-cooling time T ₂ (however, T ₂ < T ₁
A time limit (for example, 5 minutes) is set (), and the output port 48a is similarly set at a high level for that time to rotate the fan 31. That is, in the case of heater heating where the portion of the temperature measuring device 20 above the cooking chamber 14 is relatively high temperature, it takes a long time, and in the case of microwave heating, where the portion remains at a relatively low temperature, it is cooled down after a short heating operation. I do.

Note that the external heating means is not limited to the heater, and may be other heating means such as a gas burner.

〔effect〕

In the case of the cooker of the present invention as described above, the post-cooling is always performed regardless of the heating means that is driven, so that the temperature measuring device 20 can be reliably cooled and its stable operation can be ensured, and it can be exposed to high temperatures. The fan is driven for a long time after the external heating means that can be heated is driven, whereas the fan is driven for a short time after the microwave heating means, which can only reach a lower temperature, is driven for a short time, eliminating unnecessary cooling for a long time. The present invention has excellent effects such as power saving.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, in which Fig. 1 is a schematic front sectional view of the product of the invention, Fig. 2 is a schematic block diagram of the main parts of the electric circuit, and Fig. 3 is a diagram showing an example of a microcomputer. This is a flowchart of fan control. 20...Temperature measuring device, 21...Sensor box, 23...Temperature detection element, 31...Fan, 3
2...Fan drive control circuit, 48...Microcomputer.

Claims (1)

[Claims] 1. Microwave heating means and external heating means that heat the food to be cooked, a temperature measuring device that non-contactly measures the temperature of the food, a fan that cools the temperature measuring device, and measurement of the temperature measuring device. In a cooking appliance comprising a control unit that controls driving of the heating means based on temperature and drives the fan when the heating means is driven, means for setting a first post-cooling time when the external heating means is driven. and a means for setting a second post-cooling time (second post-cooling time < first post-cooling time) in the case of microwave heating means driving, and a means for setting a second post-cooling time (second post-cooling time < first post-cooling time), and a means for setting a second post-cooling time (second post-cooling time < first post-cooling time), and a means for setting a second post-cooling time (second post-cooling time < first post-cooling time) according to the driven heating means after the driving of each heating means is completed. A cooking appliance comprising a post-cooling means for driving the fan for each set first or second post-cooling time.