JP2592167B2 - High frequency heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

 The present invention relates to a high-frequency heating device.

[Prior art]

FIG. 10 is a schematic configuration diagram of a conventional microwave oven which is a high-frequency heating device, and FIG. 11 is a drive circuit diagram of a magnetron used in the microwave oven. This drive circuit is a well-known one, and a high-frequency input is rectified by a single-phase half-wave multiple voltage by a high-voltage transformer 107, a high-voltage capacitor 108, and a high-voltage diode 109 and applied to a magnetron, so that a constant microwave output is always obtained. ing. The microwave generated by the magnetron 101 is guided into the heating chamber 103 through the waveguide 102, and heats the food 104 in the heating chamber 103. The microwave introduced into the heating chamber 103 is reflected by the inner wall of the heating chamber 103 and the like, and a standing wave is generated in the heating chamber 103, so that the electric field intensity becomes uneven. And where the electric field strength is strong,
4, the microwave energy absorbed by the food 104 is so large that heating becomes too strong, and where the electric field strength is weak, the microwave energy absorbed by the food 104 is so small that heating becomes insufficient. Since it is difficult to avoid the strength of the electric field, the food is rotated by the turntable 105 to average the microwave energy absorbed by the food 104, thereby eliminating uneven heating of the food.

[Problems to be solved by the invention]

By the way, in the conventional microwave oven, since the output of the magnetron 101 is constant regardless of the rotational position of the food, when the food comes to a position where the electric field strength is weak, the energy absorbed by the food is other than the energy absorbed by the food. The energy absorbed in the part is much larger, a lot of energy is wasted, and even when the food comes to a position where the electric field strength is strong, the energy can be effectively used to heat the food, Since the output of the magnetron 101 is constant, the energy absorbed by the food cannot be increased by utilizing the position where the electric field strength is strong, and there is a disadvantage that the heating time becomes longer. In order to shorten the heating time, it is necessary to uniformly increase the electric field intensity, and there is a disadvantage that power consumption is increased. Therefore, an object of the present invention is to provide a high-frequency heating device capable of shortening a heating time without increasing power consumption by changing a high-frequency output according to a rotational position of a food.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a high-frequency heating device that irradiates a high-frequency generated by a high-frequency generating means to a heated object mounted on a rotating turntable to heat the heated object. In the above, the turntable has optical transparency, storage means for storing the relationship between the rotational position of a specific location on the turntable and the electric field strength at the rotational position, below the turntable, and A light detecting means disposed in a region having a strong electric field intensity and detecting a rotational position of the object to be heated mounted on the rotating turntable; and a rotational position of the object to be heated detected by the light detecting means. Based on the stored contents of the storage means, the output of the high-frequency generation means increases when the object to be heated is at a rotational position where the electric field strength is strong, so that the high-frequency generation means It is characterized in that an output control means for controlling the force.

[Action]

In the above configuration, it is assumed that the relationship between the rotational position of a specific location on the turntable and the electric field strength at that rotational position is stored in the storage means in advance. Then, the object to be heated is placed on the turntable and the turntable is rotated. The light detecting means disposed below the turntable and in a region where the electric field intensity is strong detects light from an oven lamp or the like transmitted through the light-transmissive turntable. When the light reaches the detecting means, the object to be heated blocks the light passing through the turntable and reaching the light detecting means, and the light detecting means does not detect the light. In this way, the rotation position of the object to be heated mounted on the rotating turntable is detected by the light detection means, and the output control means stores the rotation position of the object to be heated detected by the position detection means in the storage means. Based on the contents, the output of the high-frequency generator is controlled so that the output of the high-frequency generator increases when the object to be heated reaches a rotational position where the electric field strength is strong. Therefore, when the object to be heated comes to a position where the electric field intensity is strong, the high frequency output can be increased, and when the object to be heated comes to a position where the electric field intensity is weak, the high frequency output can be weakened. Can be heated quickly.

【Example】

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a schematic structural view of an electronic lens according to one embodiment of the present invention. In FIG. 1, 1 is an oven, 2 is a magnetron, 3 is a waveguide for guiding the microwave generated by the magnetron 2 into the oven 1, 4 is a turntable, 5 is a turntable motor, 6 is an oven lamp, Reference numeral 7 denotes an optical sensor including a phototransistor or the like. The turntable 4 is made of a light transmissive material such as glass, and transmits light from the oven lamp 6. The light sensor 7 detects the light transmitted through the turntable 4. That is, when the food 9 on the turntable 4 comes to a position covering the optical sensor 7 by the rotation of the turntable 4, the optical sensor 7 does not detect the light, and when the food 9 is at any other position, the optical sensor 7 7 detects light. On the other hand, the inside of the oven 1 has a place where the electric field intensity is strong and a place where the electric field strength is weak as described in the conventional example. On the turntable 4, it is directly below the opening of the waveguide 3 (shown by a broken line in FIG. 2). It can easily be imagined that the range is the strongest, whereas the position 180 ° opposite is the weakest. FIG. 3 shows the position of the milk on the turntable 4 and the temperature of the milk at that position by placing a cup of milk on the stationary turntable 4 and examining the position. It is a figure showing an experimental result at the time of measuring a rise value. FIG. 3 (a) shows the position of the cup, where A is placed at the center of the range indicated by the broken line, B is placed at a point symmetrical to A with respect to the center of the turntable, C and D show the cases where they are placed at positions 90 ° different from A and B, respectively. FIG. 3B shows the temperature rise values at the positions A, B, C and D. From this experimental result, it can be seen that the heating is the strongest when the food is located at the position A, and the heating is the weakest when the food is located at the position B. Therefore, when the food comes to the position A, that is, when the food comes to the position where the light from the oven lamp 6 to the light sensor 7 is blocked, the output of the magnetron 2 is increased, and the food is moved to other positions. It can be seen that the food can be efficiently heated by reducing the output at some times. FIG. 4 is a circuit configuration diagram of the present embodiment. In FIG. 4, 11 is a power outlet, 12 is a power switch, and 13 is a rectifying bridge. This rectifier bridge
13 has an oven lamp (OL) 6 and a turntable (TT)
Connecting the motor 5 and switching transistor
A high voltage transformer 17 is connected via 15. The high voltage transformer 18, the high voltage diode 19 and the magnetron 2 are connected to the secondary side of the high voltage transformer 17. Reference numeral 21 denotes a microcomputer, and a transistor 22
The opening and closing of the power supply circuit is controlled by controlling the ON / OFF of the relay contact 23 via the switch. The microcomputer 21 connects an optical sensor 7 formed by connecting a resistor 7b to a phototransistor 7a, receives a signal from the optical sensor 7, and controls on / off of a switching transistor 15 via an inverter power supply 24. Thus, the output of the magnetron 2 is controlled. An example of output control by the microcomputer 21 is shown in FIGS. 5 and 6, and another example is shown in FIGS. 7 and 8. The output control shown in FIGS. 5 and 6 shows the case of high-speed heating. Here, FIG. 5A shows the output voltage of the optical sensor 7 and FIG. 5B shows the high-frequency output of the magnetron 2. That is, the phototransistor 7a is in a conductive state during the time T0 from when the food comes to the position A where the electric field strength is strong and the light to the optical sensor 7 is stopped until the light is not blocked again, and the output voltage becomes It becomes 0V. Microcomputer 21
Indicates that the high-frequency output is 500 W when the output voltage of the optical sensor 7 is Vc, and the high-frequency output is 700 W when the output voltage of the optical sensor 7 is 0 V.
And FIG. 6 is a flowchart showing the output control operation. When the power is turned on and the turntable 4 rotates, the output is set to 500 W in step S1, and the process proceeds to step S2, where it is determined from the output voltage of the optical sensor 7 whether the food has reached the position A, that is, the position where the electric field strength is strong. If it does not come, it outputs 500 W as it is, and if it comes to the position where the electric field strength is strong, it goes to step S 3 to increase the output to 700 W. Then, in step S4, it is determined whether or not the food has passed the position where the electric field strength is strong. If not, 700W is output as it is, and if it has passed, the process returns to step S1 to output 500W again. Then, the same operation is repeated thereafter. In this way, high-speed heating is performed by increasing the output only when the food is at a position where the electric field strength is strong. It can be carried out. On the other hand, the output control shown in FIGS. 7 and 8 shows a case where the power consumption is almost the same as in the conventional case and heating is performed efficiently. Here, FIG. 7A shows the output voltage of the optical sensor 7, and FIG. 7B shows the high frequency output. That is, the microcomputer 21 sets the high-frequency output to 700 W during the time T0 when the food is at the position A, and sets the high-frequency output to 300 W while the food is at the position B where the electric field strength is weak. And the food
When it is at a position other than A and B, the output is 500W. Whether or not the food is at the position B is determined by whether or not the elapsed time from when the food has passed the position A, that is, when the output voltage of the optical sensor 7 becomes Vc is between T1 and T1 + T2. . The times T1 and T2 are obtained in advance by experiments and stored in the memory of the microcomputer 21. FIG. 8 is a flowchart showing the output control operation. That is, in steps N1 to N2, output 500 W until the food comes to the position where the electric field strength is strong, and when the food comes to the position where the electric field strength is strong, switch the output to 700 W in step N 3 and leave it as it passes that position in step N 4. Outputs 700W. After passing the position where the electric field strength is strong, steps N5 to N6
In this case, the output is 500 W until the electric field strength is reached. Then, when it comes to a position where the electric field strength is weak, the output is switched to 300 W in step N7, and 300 W is output until it passes the position in step N8. After passing through the position where the electric field strength is weak, the process returns to step N1 and switches the output to 500 W again, and thereafter the same operation is repeated. As described above, the food on the rotating turntable 4 is moved to the rotation position where the electric field strength is strong by the optical sensor 7 disposed below the light transmissive turntable 4 and at the rotation position where the electric field strength is strong. When the food is located at a position where the electric field strength is strong, the output is increased, and when the food is located at a position where the electric field strength is weak, the output is reduced. be able to. In the above embodiment, the output of the magnetron 2 was controlled by changing the input of the primary side of the high voltage transformer 17, but as shown in FIG. 9, a high voltage capacitor connected to the secondary side of the high voltage transformer 17 was used. May be controlled by changing the capacity of the power supply. That is, the microcomputer 21 connects the relay contacts 33,
By controlling 34, connecting capacitors 35 and 36 to capacitor 18 and disconnecting connected capacitors 35 and 36,
The output of the magnetron 2 may be controlled. Further, a plurality of taps may be provided in the high-voltage transformer, and the output may be controlled by switching the taps. Further, in the above-described embodiment, the position of the food is detected using the optical sensor. However, the position of the food may be detected by measuring the unbalanced load of the turntable using the gravity sensor. The detection may be performed using various sensors such as a recognition sensor and a Hall element.

As is clear from the above description, the high-frequency heating device according to the present invention is provided below the turntable having optical transparency and
The light detecting means disposed in the region where the electric field strength is strong detects that the object to be heated mounted on the rotating turntable has reached the rotation position where the electric field strength is strong, and the output control means detects the position. Based on the rotational position of the object to be heated detected by the means, and the relationship between the rotational position of the specific location on the turntable stored in the storage means and the electric field intensity at that rotational position, the object to be heated is As the output of the high-frequency generator increases when a strong rotation position is reached,
Since the output of the high-frequency generator is controlled, the object to be heated can be efficiently heated, and thus the heating speed can be increased without increasing power consumption.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of a high-frequency heating apparatus according to the present invention, FIG. 2 is a diagram for explaining a place where the electric field strength is high on the turntable in the above embodiment, and FIG. FIG. 4 is a circuit diagram of the above embodiment, FIG. 5 is a time chart for high-speed heating in the above embodiment, FIG. 6 is a flowchart showing the operation in that case, FIG. 8 is a time chart in the case of the efficient heating in the above embodiment, FIG. 8 is a flowchart showing the operation in that case, FIG. 9 is a circuit diagram of another embodiment of the present invention, and FIG.
FIG. 10 is a schematic configuration diagram of a conventional high-frequency heating device, and FIG. 11 is a circuit diagram thereof. DESCRIPTION OF SYMBOLS 1 ... Oven, 2 ... Magnetron, 3 ... Waveguide, 4 ... Turntable, 5 ... Motor, 6 ... Oven lamp, 7 ... Optical sensor, 9 ... Heated object, 21 ... Microcomputer, 22 ... Inverter power supply.

Claims (1)

(57) [Claims] 1. A high-frequency heating apparatus configured to irradiate an object to be heated mounted on a rotating turntable with a high-frequency wave generated by a high-frequency generator to heat the object to be heated. Storage means having optical transparency and storing a relationship between a rotational position of a specific portion on the turntable and an electric field intensity at the rotational position; and a region below the turntable and having a strong electric field intensity And a light detecting means for detecting a rotation position of the object to be heated mounted on the rotating turntable; and a rotation position of the object to be heated detected by the light detection means and an internal storage of the storage means. Output control means for controlling the output of the high-frequency generating means so that the output of the high-frequency generating means increases when the object to be heated reaches a rotational position where the electric field intensity is strong. And a control means.