JPH0781716B2 - Heating device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to automation of heating process, using a distance measuring sensor and a gas sensor, to detect a position of a placing plate on which an object to be heated is placed, and an object to be heated. The present invention relates to a heating device realized by monitoring the generation of water vapor or gas from the air.

2. Description of the Related Art In a heating device such as an electric oven or a gas oven that raises the ambient temperature in a heating chamber to cook an object to be heated by convection heating, the baking temperature and the cooking time differ depending on the type of the object to be heated. Generally, different keys are provided on the operation panel for each type of object to be heated. In other words, for oven dishes such as cookies, cakes, chows, and butter rolls, the user presses different keys on the operation panel to start cooking.

Furthermore, in such oven cooking, in addition to selecting the desired baking temperature and time with another key as described above, in order to obtain the optimum heat distribution for the object to be heated, a plurality of shelf rails installed in the heating chamber It is usual to select a predetermined one of them and selectively position the placing plate on which the object to be heated is placed.

This is because a delicate temperature gradient naturally occurs in the up-down direction of the heating chamber, and it is necessary to select an optimum upper-lower heat balance according to the type of the object to be heated.

Problems to be Solved by the Invention As described above, in the conventional heating device for performing oven cooking by convection heating, the keys must be separately separated depending on the types of objects to be heated such as cookies and cakes. Was giving a feeling of complexity. In addition, it was not clear whether or not the plate was correctly placed on the predetermined shelf position, and the user had to spend anxious time until the cooking was completed.

In view of such a background, the present invention is configured so that the cookies and cakes are automatically determined based on the position of the plate and the generation of water vapor or gas from the object to be heated, and cooking can be performed with a single heating command key. It is intended to realize the fully automatic heating device.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a distance-measuring sensor in which a control unit configured by a microcomputer receives and transmits ultrasonic waves, and an object to be heated or a placing plate. Detect the distance to. Furthermore, a gas sensor is provided to monitor the generation of water vapor or gas from the object to be heated.

In the heating device of the present invention, the microcomputer as the control unit controls the distance measuring sensor to receive the ultrasonic wave, which is reflected by the plate or the object to be heated, and the time until the sensor receives again is counted. Based on this time, the distance to the plate or the object to be heated is calculated, the position of the plate is determined, and it is estimated which menu of the oven dish is about to be cooked. Furthermore, the gas sensor monitors the generation of water vapor and gas from the object to be heated, and judges whether or not there is an error in the menu estimation. Then, according to this estimation and judgment, the method of supplying power to the heating means is automatically changed to realize fully automatic heating with a single key.

Example A heating apparatus according to an example of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of the main body of the heating device according to the present invention.
A door body 2 is pivotally supported on the front surface of the main body 1 so as to be openable and closable, and an operation panel 3 is provided. A single fully automatic key 4 is arranged on the operation panel 3.

FIG. 1 is a block diagram showing the configuration of such a heating device. The heating command input from the fully automatic key 4 is decoded by the control unit 5 including a microcomputer. Then, the control unit 5 measures the distance D to the placing tray 8 on which the object 7 to be heated is placed by using the distance measuring sensor 6 which receives and transmits ultrasonic waves.

On the opposite side walls of the heating chamber 9, paired shelf rails 10
Are provided in a plurality of stages, and the shelf position is selected according to the object to be heated. For example, cookies are on the top, puffs and butter rolls are on the middle, cakes are on the bottom, and so on. Which shelf position is appropriate is determined mainly by the design of the heating chamber, and the optimum shelf position is determined by the heat distribution to the upper and lower heaters, the overall heat balance, and the material distribution of the dough.

Now, when the loading tray 8 moves to the upper stage, the detection distance D becomes the smallest, and the distance D increases as it goes to the middle and lower stages. That is, by detecting the distance D, the position of the placing plate can be known.

The mounting tray 8 is a rectangular metal part as shown in the perspective view of FIG. 3, and the flange portion of the peripheral edge thereof rides on the shelf rail. The whole is subjected to a surface treatment such as enamel to increase the corrosion resistance.

Returning to FIG. 1, with the above configuration, the control unit 5 can detect the position of the plate 8 using the distance measuring sensor 6, and based on this determination, from the shelf position selected by the user, On the contrary, it is possible to estimate the menu of the oven dish that is about to start. In other words, the type of object to be heated is estimated by reversely using the regulation of the selection of the shelf position, such as cookies for the upper stage, puffs and butter rolls for the middle stage, and cake for the lower stage.

After estimating the menu, the control unit 5 starts power supply to the heating means 12 via the driver 11.

The heating means 12 is a sheet-like electric heater arranged vertically outside the heating chamber in the present embodiment, but may be an electric oven of a hot air circulation system, or, of course, a gas oven equipped with a gas burner. Needless to say, can be applied.

The control unit 5 sets the heating temperature corresponding to the estimated menu and controls the power supply to the upper and lower heaters while monitoring the temperature inside the heating chamber with the temperature sensor 13. The distribution of electric power to the top and bottom and the heating time are also changed according to the estimation of the menu.

When the heating is started, the gas sensor 14 is used to
Water vapor or gas emitted from is detected. Then, the estimated menu name is confirmed by monitoring the occurrence.

FIG. 4 is a time chart showing such a discrimination method, in which the horizontal axis represents elapsed time and the vertical axis represents changes in absolute humidity.

For example, although it is not possible to determine whether it is a shoe skin or a butter roll even if the shelf position of the loading tray 8 is in the middle stage, one can be determined by looking at the time change of humidity in this way.

That is, in the case of the husks, the humidity rises and then begins to dry, and when it decreases, it is baked, but in the butter roll, the humidity continues to increase.

Similarly, in cookies, the humidity, like that of the crust, decreases after rising, and in the cake, the steam continues to increase slowly.

By monitoring the generation of humidity in this way, the menu name can be confirmed together with the shelf position, and the heating temperature can be corrected at that time. For example, suppose that the shelf position is in the middle, and it is presumed that it is a crust or butter roll, and when cooking was started at 180 ° C, it was determined that it was a cookie because of the way steam was generated. 170 ° C suitable for cookies at this point
The temperature can be finely adjusted.

Of course, the heating time can be changed, and the finishing time can be detected by a gas sensor.

Reference numeral 15 is a distance sensor detection circuit, 16 is a temperature sensor detection circuit, and 17 is a gas sensor detection circuit.

Although an A / D converter or the like is used as the temperature sensor detection circuit 16, a microcomputer having a built-in A / D circuit can be used as the control unit 5.

If a humidity sensor is selected as the gas sensor, the detection circuit 17 and the control method thereof are described in, for example, JP-A-51-134951.
It can be realized by the publication.

Now, a configuration example of the distance measuring sensor 6 and its detection circuit 15 will be described. FIG. 5 shows an ultrasonic sensor as an example of the distance measuring sensor.

The ultrasonic sensor includes a piezoelectric element 18, a conical resonator 20 that engages with the piezoelectric element 18 via a coupling shaft 19, a terminal 22 that is connected to the piezoelectric element 18 by a lead wire 21, and the terminal 22 is fixed. Terminal plate 23, a case 24 forming an outer shell, a beam shaping plate 25 covering an opening of the case 24 on the conical resonator 20 side, and a terminal plate
The sound absorbing sheet 26 is provided on the inner surface of 23.
(National Technical Report P.504 ~ 514 Vol
Next, FIG. 6 is a block diagram showing a configuration example of the detection circuit 15 of the ultrasonic sensor.

The control unit 5 is composed of a microcomputer, and by performing timing control, one ultrasonic sensor transmits an ultrasonic wave of several tens of kHz, and at the time of reception, it is switched to a wave receiver to operate.

27 is a transmitting circuit and 28 is a receiving circuit. The comparison circuit 29 compares the received signal with the reference voltage, latches the received signal exceeding this reference voltage, and inputs it to the control unit 5. The control unit 5 counts the time from the transmission of the ultrasonic waves to the reception of the ultrasonic waves, calculates the distance to the mounting plate from the propagation speed of the ultrasonic waves, and detects the position of the mounting plate from this. Microcomputers usually take a few microseconds to a few tens of microseconds to execute one instruction, but since the speed of sound is 343 m / s (at 20 ° C), it takes about 30 microseconds to travel 1 cm. It takes twice as long as the time from the transmission to the reflection on the plate and the reception. By using ultrasonic waves, a few cm to a dozen cm with a microcomputer
It is possible to detect the distance to the only plate.

With the above configuration, it is possible to detect the position of the plate and the generation of water vapor or gas from the object to be heated, and it is possible to cook a plurality of menus with a single heating command key, for example, a "candy" key.

The present invention is also applicable to a so-called oven microwave oven in which a microwave oven and an electric or gas oven are combined.

EFFECTS OF THE INVENTION As described above, the heating device of the present invention is provided with the distance measuring sensor for receiving and transmitting ultrasonic waves and the gas, so that the microcomputer as a control unit controls the position of the plate and water vapor or gas from the object to be heated. Is detected, the type of the object to be heated is measured from this, and the power supply to the heating means is changed, and a wide range of objects to be heated can be automatically heated with a few keys.

Also, even after starting heating in this way, the way steam is emitted is monitored, so even if a cookie is baked in the middle stage instead of the upper stage, the heating temperature and the method of supplying power to the upper and lower heaters must be changed. You can also It is also possible to detect the finish and automatically finish cooking.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a heating apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the main body, FIG. 3 is a perspective view of a placing plate, and FIG. 4 is water vapor from an object to be heated. 5 is a sectional view of an ultrasonic sensor as an example of a distance measuring sensor, and FIG. 6 is a circuit block diagram showing a configuration example of a detection circuit of the ultrasonic sensor. 4 ... Fully automatic key, 5 ... Control unit, 6 ... Distance measuring sensor,
7 ... Object to be heated, 8 ... Plate, 9 ... Heating chamber, 10 ...
Shelf rail, 12 ... Heating means, 14 ... Gas sensor.

Claims (1)

[Claims] 1. A heating chamber for accommodating an object to be heated, a heating unit provided in the heating chamber, and a control unit including a microcomputer for controlling power supply to the heating unit.
The placing plate on which the object to be heated is placed, the distance measuring sensor for receiving and transmitting ultrasonic waves, and the gas sensor for detecting water vapor or gas generated from the object to be heated, wherein the plate is the heating chamber. Positioned at a predetermined height among a plurality of shelf positions, and the control unit uses the distance measuring sensor to detect the distance from the distance measuring sensor to the object to be heated, or the plate described above. The position of the plate in the heating chamber is determined, and the gas sensor also monitors the generation of steam or gas generated from the object to be heated. Therefore, the heating device configured to change the method of supplying power to the heating means.