JPS628150Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a safety device for a high-frequency heating device with a heater.

Conventionally, there have been devices equipped with a heater to compensate for the problem of not browning the object to be heated, which is a drawback of high-frequency heating devices. Among those equipped with a heater, there are those whose purpose is simply to brown the food, and those which have the function of oven cooking by raising the temperature of the entire heating chamber.

When using this high-frequency heating device with a heater, the latter one with an oven function is very convenient because it expands the heating methods and expands the cooking repertoire.

However, since the entire heating chamber reaches a high temperature, the temperature of electrical parts and the like increases rapidly, making it very difficult to design. Further, such a high frequency heating device having an oven function is provided with a temperature controller to maintain the temperature inside the oven at a value appropriate for each dish. Considering various factors such as price, quality, and productivity, a liquid expansion type temperature controller is generally used.

In this liquid expansion type, the heat sensitive part and the mechanism part are separated and connected by a metal tube. At this time, the heat sensitive part and metal tube mechanism part are
It is filled with a liquid that responds precisely to temperature (thermal expansion) and operates a switch that turns the heater on and off. The disadvantages of this liquid expansion type are the heat-sensitive part, metal tube, mechanical part, and
If the connection is damaged, liquid may flow out, and the temperature may not be controlled or the mechanism may operate slowly. Further, even if the liquid does not flow out, the above-mentioned malfunction may occur even if the metal tube is bent with an extremely small opening. In this case, mechanically the switch will not turn off, and if the oven continues to operate as it is, the temperature inside the oven will become extremely high. As a result, the heat resistance of electrical parts becomes a problem, resulting in a very dangerous situation. At this time, it is necessary to install a device that can detect an abnormal temperature rise in the oven and shut off the power supply, but this will increase costs due to the increase in parts, and the cost of raw materials will be affected by product prices. Consumers will bear some of the burden. Therefore, the present invention has a greatly improved structure that detects abnormal temperature rises in the oven using the high-frequency oscillator temperature rise prevention device conventionally used in high-frequency heating devices. .

An embodiment of the present invention will be described below with reference to the drawings.
Figure 1 shows a high-frequency heating device 1 that incorporates a heater 2 and has an oven function.
The temperature inside the heating chamber 3 is increased by this. Temperature control is performed by a liquid expansion type temperature regulator 4 shown in FIG. The structure of this temperature regulator 4 consists of a heat sensitive section 5, a metal tube 6, and a mechanism section 7, into which a liquid is injected.

If the heat sensitive part 5, metal tube 6, mechanism part 7, and their connecting parts are damaged, there is a risk that the injected liquid will flow out and temperature control will not be possible. In particular, the metal tube 6 is a very thin tube, and when bent at a small opening, as shown in Fig. 3, a→b→
As shown in c, it becomes difficult for the expansion of the liquid in the heat-sensitive part to be transmitted from the heat-sensitive side A to the mechanism side B, and the switch in the mechanism part 7 turns ON and OFF slowly or does not turn OFF. Therefore, if the oven is operated continuously at a very high risk, the temperature inside the oven will reach a very high temperature, and due to the heat resistance of the electrical parts, it is inevitable that a very dangerous situation will occur. At this time, it is necessary to install a device that detects an abnormal temperature rise in the oven and shuts off the power.
As shown in the figure, a temperature overrise prevention device 9 is installed in a part 8 of the heating chamber 3.
must be installed. but,
This is not very desirable because it increases the cost due to the increase in the number of parts. Therefore, we have made technical improvements such that the overtemperature rise prevention device 11 for protecting components, which has been conventionally attached to the high frequency oscillator 10, can also detect abnormal temperature rises due to a malfunction of the temperature controller in the heating chamber 3. It has a structure. As shown in FIG. 6, a part of the high frequency oscillator 10 and a part 8 of the heating chamber 3 are bridged by a heat conductor, and the overtemperature rise prevention device 11 is connected to a part of the heat conductor 12. When the high-frequency oscillator 10 is operated as a high-frequency heating device as shown in Figure 7, if the temperature of the high-frequency oscillator 10 rises abnormally due to some malfunction, the heat will be transferred as shown by the solid arrow. When the temperature rises abnormally due to a malfunction of the temperature controller 4 in the heating chamber 3, the heat is transmitted as shown by the dotted arrow 14 and the overtemperature rise prevention device 11 is activated. It is.

However, in reality, when the above structure was adopted, a number of disadvantages occurred. The problem is that when used as a high-frequency heating device in a state close to dry firing (with a light load), the temperature of the high-frequency oscillator 10 rises too much, and the heat is transferred via the thermal conductor 12, preventing excessive temperature rise. Device 11 has malfunctioned. in the end,
Even though the high-frequency heating device has not malfunctioned,
If continuous operation is performed when the load is light, that is, when there are few objects to be heated, the overtemperature rise preventer 11 will turn off. At this time, there is a way to make the thermal conductor 12 with a material with low thermal conductivity, but if it is made with a material with low thermal conductivity, the high frequency oscillator 10 will not be able to operate the overtemperature rise preventer 11 when a real abnormality occurs. It was difficult for heat to be transferred to the surface, and conventional performance could not be maintained.
Further, the temperature inside the heating chamber 3 becomes high when the oven is in use, and in the installation as shown in FIG. 7, the overtemperature rise preventer 11 malfunctions even during normal operation. Although this may be set to a high temperature given the operating temperature of the overtemperature rise preventer 11, it is considered necessary to eliminate the difference in the abnormal temperature rise rate between the high frequency oscillator and the heating chamber 3. .

Therefore, the present invention solves the above problems and provides a highly technically improved structure. In order to prevent the overtemperature rise preventer 11 from malfunctioning even when the high frequency heating device is operated under a light load, the cooling motor 1 of the high frequency oscillator 10 is installed as shown in FIG.
The wind generated by No. 5 is directly blown onto the heat conductor 12 and the overtemperature rise preventer 11 to form a high frequency oscillation device, and the device is characterized in that it is installed in a position where it is constantly cooled during operation. Further, as shown in FIG. 9, a heat conductor 16 is provided so that the overtemperature rise preventer 11 is mounted floating above a portion 8 of the heating chamber 3. The thermal conductor 16 can be made of the same material as the thermal conductor 12 or a different material so that the thermal conductivity can be easily made the same or different, thereby eliminating the temperature difference between the high frequency oscillator 10 and the heating chamber 3. This can be easily set by selecting materials for the thermal conductors 12 and 16 that are suitable for the operating temperature of the overtemperature rise preventer 11.

As described above, with this invention, abnormalities in the high-frequency oscillator and the heating chamber can be easily detected using a common overtemperature preventer, and technical improvements have been made to eliminate harmful effects such as malfunctions. It is possible to provide a safe high-frequency heating device with a heater.

Additionally, since the overtemperature rise preventer is mounted floating above a portion of the heating chamber, the degree of heat conduction from the heating chamber can be delicately set, allowing accurate operation as a safety device.

Furthermore, when the magnetron is operating, the heat conduction from the heating chamber is suppressed by the wind generated by the cooling motor, and when the heater is heating, the cooling motor is stopped, and the heat conduction, which has a lower thermal conductivity than the magnetron side, is suppressed. Since the temperature is transmitted to the overheat protector by the body, different dangerous temperatures of the magnetron and the heating chamber can be easily set in the overheat protector.

[Brief explanation of the drawing]

Figure 1 is a front view of the high-frequency heating device with a built-in heater, Figure 2 is a perspective view of the main part of the liquid expansion temperature controller, Figure 3 is a sectional view of the metal tube of the liquid expansion temperature controller, and a is normal. b is a cross-sectional view when it is slightly bent, c is a cross-sectional view when it is bent at a small opening, Fig. 4 is a cross-sectional view of a conventional high-frequency heating device, and Fig. 5 is a cross-sectional view of the same high-frequency heating device. Figure 6 is a cross-sectional view of a heating device equipped with a conventional high-frequency oscillator protection device and one overtemperature preventer to detect abnormal temperatures in the heating chamber. A cross-sectional view of a device in which abnormal temperature in a room is detected by a common overtemperature rise prevention device, Fig. 7 is an enlarged view of the main part of Fig. 6, and Fig. 8 is a high frequency device with a heater showing an embodiment of the present invention. FIG. 9 is a rear view showing the heating device with the exterior removed, and FIG. 9 is an enlarged cross-sectional view of the essential parts. 3... Heating chamber, 11... Overtemperature rise prevention device, 1
2,16...Heat conductor.

Claims (1)

[Scope of utility model registration request] A part of the magnetron that supplies radio waves into the heating chamber and a part of the heating chamber have two different thermal conductivities.
the joint is spaced apart from the heating chamber and the magnetron, and the thermal conductor on the magnetron side is made of a material having a higher thermal conductivity than the thermal conductor on the heating chamber side. A high-frequency heating device with a heater configured to cool the two types of heat conductors and the overtemperature rise preventer by wind generated by a cooling motor during high-frequency oscillation.