JPS6137757B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating cooker using a three-phase power supply, and particularly relates to a circuit configuration of a heating cooker equipped with a high-frequency heating device and a power supply heating device, and improves efficiency in heating work. The purpose is to improve usability.

Traditionally, cooking equipment used in general households has been required to have more efficient cooking performance. The need for secondary heating using other equipment (which can create brown marks) due to the so-called non-burning of high-frequency heating is a major issue, and recently devised high-frequency heating and electric heating have been developed to achieve the same heating. The indoor method is highly praised for its effectiveness.

On the other hand, improving the efficiency of cooking is an even more important theme in kitchens of cafeterias, restaurants, hotels, etc. than in homes. It is hoped that the price will be lower. Conventionally, this commercial equipment has been a single-function device, that is, an electric heating device and a high-frequency heating device have been separate devices, and it has naturally been desirable to solve the above-mentioned problems.

The purpose of the present invention is to improve the cooking efficiency of such a commercial heating device and to further reduce running costs. The purpose is to shorten the heating time by performing both high-frequency heating and electric heating independently in the heating chamber, or simultaneously by operating a knob provided on the main body.

FIG. 1 is a schematic side cross-sectional view showing an embodiment of the present invention, and the structure is as follows. A heating chamber 4 is provided in a part of the main body 1 and has a door 3 forming a part of its wall surface which allows the object to be heated 2 to enter and exit. Heating chamber 4
Near the top wall 5 and bottom wall 6, three electric heaters 7 are installed at the top and bottom to enable electric heating. These three sets of heaters are connected to a heating selection means 8 for selecting a heating method;
It is connected between each phase of a three-phase power supply via a temperature control means 9 for adjusting the heating temperature. Although not shown, the temperature control means 9 allows the heating temperature to be arbitrarily controlled by a knob 16 provided on the outer surface of the main body 1.

On the other hand, a part of the upper wall 5 of the heating chamber 4 is made possible to excite high frequency waves into the heating chamber. opening 10
A waveguide 12 guides the high frequency waves emitted from one magnetron 11 as a high frequency generating means to the opening, and an opening cover 13 is provided to prevent foreign matter from entering the waveguide 12 from the opening 10. .
The magnetron 11 is connected to a three-phase power source via a power supply device 14 and the aforementioned heating selection means 8, and obtains the power necessary for its oscillation.

FIG. 2 is a diagram showing the circuit configuration of the present invention.
Electric power led into the main body 1 from a three-phase power source is led to the heating selection means 8 via an input control device 15 comprising various safety devices, a time switch for setting the heating time, and the like. The heating selection means 8 connects the three circuits in one direction or two directions S _1a and S _1
b , _S1c , and when the knob 16 provided outside the main body 1 is set to position 1 as shown in Fig. 2b, the COM terminal 3 and _S1
Both _a to _c are in one direction, S _1a and _b are in one direction in 2, S _1
c is connected in two directions. This heating selection means is always connected to either contact 1 or 2 no matter what position the knob 16 is set to. The contacts 1 are connected to three input terminals of a power supply device 14 that supplies a predetermined power to the magnetron 11 . The power supply device generally has the same configuration as a power supply device used for single-phase power supply, but it is small because the output required for each equivalent is only about 1/3 of that of a single-phase transformer. The output of the power transformer for each phase, which is a fero-resonant constant voltage power supply, is voltage doubled and half-wave rectified by diodes D _1a , _b , _c , and the three outputs are combined by diodes D _2a , _b , _c , and the magnetron 11. FIG. 3a schematically shows the waveform of the current flowing through the magnetron 11. That is, depending on the position of the knob of the heating selection means 8 mentioned above,
The phase connected to one of S _1a , _b , and _c supplies the magnetron 11 with the power necessary for oscillation.
A high frequency is generated during a half cycle in the current phase of that phase. Furthermore, in position 1 of the heating selection switch, all phases are
Since power is supplied to the magnetron 11, a current as shown in FIG. 3a flows through the magnetron 11, and a rated high-frequency output is generated. Position 2 is 2/30 of the rated high frequency output, position 3 is 1/30 of the rated high frequency output, and position 4 is 1/30 of the rated high frequency output.
In this case, the high frequency output is 0. The waveforms of the current flowing through the magnetron 11 at this time are shown in FIGS. 3a to 3d.

On the other hand, in each switch in the heating selection means 8, in order to keep the temperature in the heating chamber 4 constant, the output switch of the temperature control device 9 turns off the input power when the set temperature is exceeded. S _2a , _b , _{and c} are connected to the electric heater through the contacts that turn ON below the set temperature.

As a result, the high frequency output is the rated output at position 1 of the heating selection means 8, the high frequency output is 2/3 at the electrothermal output O ₀ position, the high frequency output is 2/3 at the electrothermal output 1/30 position, and the high frequency output is 1/3 at the electrothermal output 2/30 position. In No. 4, the high frequency output is O, the electric heating output is the rated output, and three types of heating can be arbitrarily selected: high frequency heating only, electric heating only, and simultaneous high frequency and power supply heating. Furthermore, the present invention provides input power to power transformers T _a , _b , _c as loads of each phase and heaters H _a ,
The input powers of _b and _c are set to almost the same value.

Therefore, the total sum of input power in each position of the cooking selection means 8 is always equal.

By using the above configuration, the following effects could be obtained.

First of all, as per the initial objective, after reducing running costs by using a three-phase power supply, by using simultaneous heating, the object to be heated can be quickly heated to the inside by high frequency heating, and at the same time, the outer surface can be melanized by heater heating. In other words, it became possible to create dark eyes. Depending on the food, the ratio of the heater output for browning and the high-frequency output for heating the interior is not constant. High frequency heating is done quickly,
For example, cakes that are difficult to heat by electric heating.
When cooking a large volume of meat that takes time to heat even with high-frequency heating, the optimal ratio of output between high-frequency and electric heaters is different when simultaneously heating.

In the present invention, this ratio can be changed only by changing the position of the cooking selection means, thereby increasing cooking efficiency and improving usability.

Secondly, since the input power is always constant even when switching to each position, there is no waste in the power supply equipment and the equipment can be used effectively. In addition, it was possible to eliminate the loss of interphase balance due to changes in input current and the effects on external equipment due to changes in power supply voltage.

Furthermore, since the high-frequency generator has a circuit configuration that uses one magnetron, the external size of the main unit can be made smaller compared to the conventional three-piece system, which saves space and makes effective use of space in the kitchen. Summer. In addition, as shown in Figure 3, the voltage applied to the magnetron becomes close to direct current, and the ratio of the peak to average current flowing through the magnetron becomes smaller, making it possible to extend the lifespan, which is most important for commercial equipment. Ta. Furthermore, unnecessary radiation other than the fundamental wave caused by the fact that normal voltage is not applied during rise and fall due to small changes in current can be significantly reduced, and there is no longer any noise disturbance to surrounding radio equipment. Furthermore, regarding the heating unevenness performance during high-frequency heating that tends to cause uneven heating of the heated object, if three magnetrons are used and the output is changed by changing the number of operating magnetrons, the oscillation position of the magnetron will change depending on the output. However, according to the present invention, the high frequency is always irradiated into the heating chamber from the same location, so there is no change in heating unevenness performance due to changes in output, and any object is always heated in the same way. , easy to use.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a heating cooker showing an embodiment of the present invention, FIG.
The figure shows the phase relationship between the current flowing through the magnetron and the current flowing through the heater at each position of the cooking device. 1...Main body, 4...Heating chamber, 7...Electric heater, 8...Cooking selection means, 11...Magnetron, 14...Power supply device, 16...Knob.

Claims (1)

[Claims] 1 A heating chamber provided in the main body, a high frequency oscillation means for supplying high frequency energy into the heating chamber, an electric heater that heats the food stored in the heating chamber, and a heating chamber that generates the high frequency while receiving power from a three-phase power supply. A power supply device that supplies power to the oscillation means and the electric heater, and a temperature control means that controls the temperature in the heating chamber, and either the high frequency oscillation means or the electric heater is always connected to each phase of the power supply device. What is claimed is: 1. A heating cooking device characterized in that the heating device is connected as a load, and the user can select whether to use the high frequency oscillation means or the electric heater alone or at the same time.