JPH0525539Y2 - - Google Patents

Description

[Detailed description of the invention] (Application field and overview of the invention) The present invention relates to an overheating prevention device for a rice cooker (hereinafter referred to as an overheating prevention device), and is a heat-responsive device that operates at the end of rice cooking. If it doesn't work,
By stopping the heating operation by the heating device using a separate control device and setting this stopping operation temperature to the temperature at which edible burnt occurs in the cooked rice, it is possible to prevent overheating due to malfunction of the thermal response device that is difficult to reproduce. This enables reuse in the same way as in normal conditions.

(Prior art and its problems) In conventional rice cookers, during normal rice cooking, the completion time of rice cooking is detected by detecting changes in the temperature of the rice cooker or the temperature of the combustion chamber. The temperature of the rice cooker is 140℃~145℃.
Heating is stopped when the temperature reaches ℃.

This point corresponds to the point at which most of the water in the rice cooker has impregnated into the rice grains, and the temperature at the bottom of the rice cooker rapidly rises.

In order to detect the temperature at this time and automatically shut off the gas circuit, a configuration as shown in FIG. 4 is adopted.

That is, in order to detect the temperature at the center of the bottom of the rice cooker A, a cylindrical body 11 equipped with a thermal response device in the center of the burner 1 is movable up and down in the lower case B that houses the combustion mechanism and the control mechanism, and is mounted on a spring. 12 is placed in a state where it is biased upwardly, and the set temperature is set at 140°C to 145°C on the inner surface of the top part of this cylindrical body 11 as described above.
A soft ferrite 13 set to
A permanent magnet 14 that can be moved up and down relative to the cylindrical body 11 is provided within the cylindrical body 11.

This permanent magnet 14 is interlocked with the valve device 2 and the operating lever 3 via an interlocking mechanism.During rice cooking, when the operating lever 3 is operated, the permanent magnet 14 is attracted to the soft ferrite 13, and the valve device 2 is opened. placed in a valve state.

When the above-mentioned parts are in normal condition, when the inside of the rice cooker reaches the set temperature, Soft Ferrite 1
3, the permanent magnet 14 separates from the soft ferrite 13, the valve device 2 closes, the gas circuit to the burner 1 is cut off, and heating is stopped.

However, in very rare cases, when the separation motion of the permanent magnet 14 does not proceed smoothly, even though the mutual attraction between the soft ferrite 13 and the permanent magnet 14 has disappeared due to the transformation of the soft ferrite 13, The valve device 2 may not close the valve, resulting in an overheated state.

Normally, an overheat prevention device is installed, so even if such a situation occurs, the appliance will not become abnormally heated and cause a fire accident, but the rice in rice cooker A may be black. It becomes a burnt state.
In addition, the inner surface of the rice cooker A is also heavily stained with burnt dirt, which is difficult to remove. Therefore, when the above-mentioned malfunction occurs, it is treated in the same way as a device with other fatal defects (for example, a device with damaged soft ferrite 13).

However, as mentioned above, malfunctions due to the above-mentioned causes occur extremely rarely and are not reproducible, and in most cases, if the product is reused, it can be used as is.

In this way, conventional rice cookers have the inconvenience of being treated as a fatally defective product if a minor malfunction occurs in the thermal response device that is not reproducible, even though the rice cooker is a good product that can be reused. .

This is because even in the case of malfunction due to the above-mentioned causes, heating can only be stopped in an abnormally overheated state, similar to other fatal defects.

(Technical issue) The present invention aims to prevent the malfunction resulting from the malfunction from turning into a state similar to a fatal failure when a non-reproducible malfunction that occurs extremely rarely occurs in a thermally responsive device. The challenge is to make it possible to reuse it in the same way as when it is used.

(Means) The technical means of the present invention taken to solve the above-mentioned technical problem is to sense the completion point of rice cooking using a heat-responsive device, and to heat the rice cooker A using the output of this heat-responsive device. In the device configured to operate a heating stop means for stopping the heating, an over-rise temperature detecting means is provided separately from the heat-responsive device, and the over-rise temperature detecting means detects a temperature change proportional to a temperature change within the cooking rice. The output of the over-rise temperature detecting means is input to the heating stop means, and the set temperature of the over-rise temperature detecting means is set to be higher than the temperature at the time of completion of cooking and to a degree that causes edible burnt on the cooked rice. The temperature was set to correspond to the internal temperature of the rice cooker.

(Operation) The above technical means of the present invention operates as follows.

Under normal conditions, when the temperature inside the rice cooking pot reaches the rice cooking completion temperature, heating is stopped by the output of the thermal response device.

Next, if the rice cooking is not completed (stops heating) due to malfunction of the thermal response device, the heating will proceed further, but the temperature inside the rice cooker A will further rise, causing some burnt on the rice. When this occurs, at this point, the output from the excessive temperature detection means is input to the heating stop means, and further heating of the rice cooker A is stopped. In this state, rice cooker A
The cooked rice is not in a black charred state and has an edible charred appearance, so it can be eaten as is.

If the above-mentioned overheating state is caused by a minor malfunction of the heat-responsive device that is not reproducible, then the next time the rice will be cooked normally, and the rice in the rice cooker A will be cooked by the output of the heat-responsive device. Heating is stopped when the completion temperature is reached.

(Effects) Since the present invention has the above configuration, it has the following unique effects.

Even if a malfunction occurs in the heat-responsive device, which occurs only rarely and is not reproducible, the overheating prevention device will stop the rice cooking operation after the rice cooking is completed. When the rice is cooked, it is not judged to be abnormal because it has some edible burnt.
It will be reused as is. When the rice is reused, the rice cooking operation is stopped when the rice cooking is completed by the normal operation of the thermal response device.

Therefore, in the event that a malfunction that occurs only rarely and is not reproducible occurs, the inconvenience of being left unused because the rice cooker is determined to be malfunctioning can be eliminated.

Another great advantage is that the cooked rice that is stopped when the rice cooking operation is stopped due to the operation of the overheat prevention device can be eaten as is.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

This embodiment is a gas rice cooker that employs a thermal response device similar to the conventional example described above, including a cylinder body 11, a spring 12, a soft ferrite 13, and a permanent magnet 14.
is similarly assembled into the central through-hole of the burner 1, and the permanent magnet 14 is attached to an elevating plate that loosely fits into the guide shafts 15, 15 provided in the cylinder body 11.
This elevating plate regulates the elevating trajectory of the permanent magnet 14 so that it is appropriate for the soft ferrite 13. Further, the permanent magnet 14 is connected to the upper end of an elevating shaft 16, and at the lower end of this elevating shaft 16, there is a swing lever 17 that interlocks with the valve device 2 and the operating lever 3 described above, as shown in FIG. It is arranged in this manner.

Therefore, by operating the operating lever 3, the tip of the swinging lever 17 is lifted, and the permanent magnet 14 is attracted to the soft ferrite 13 via the lifting shaft 16, and at the same time, the valve device 2 is opened. , burner 1 burns, and rice cooker A is heated. When the thermal response device operates smoothly at the rice cooking completion temperature, the permanent magnet 14 separates from the soft ferrite 13 due to the above-mentioned action, the lifting shaft 16 and the swinging lever 17 descend, and the valve device 2 closes to complete the rice cooking. Heating is stopped.

Next, in this embodiment, a bimetal switch 4 is employed as an excessive temperature detection means, and this is attached to the lower end of a guide cylinder 18 that holds the cylinder 11 so as to be able to move up and down.

This bimetallic switch 4 is housed at the lower end of a tube 41 with good heat transfer, and as shown in FIG.
2, and this flat part 42 is attached and fixed to the body of the guide cylinder 18. Therefore, the bimetal switch 4 has a guide tube 18 that is proportional to the temperature change of the rice cooker A.
The body undergoes a corresponding metamorphosis.

As shown in FIG. 2, this bimetal switch 4 is inserted into a thermocouple circuit 50 of a pilot safety device 5 inserted upstream of the valve device 2 of the gas circuit. Therefore, both when the pilot burner 6 disposed near the burner 1 disappears and the temperature of the thermocouple 51 drops, and when the bimetal switch 4 becomes temperature-sensitive and becomes disconnected. The pilot safety device 5 shuts off the gas circuit.

In this embodiment, the operating temperature of the bimetal switch 4 is set at 100°C, which corresponds to the temperature at the center of the bottom of the rice cooker A, which is 200°C.

In the above embodiment, 4 is a bimetal switch, but it may also be a thermostat.
In any case, any excessive temperature detection means may be used as long as the contact point can be reset again.

In addition, an overheat prevention device separate from the bimetal switch 4 is provided, and the operating temperature of this device is set to the bimetal switch 4.
The temperature may be set higher than the set temperature.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part of an embodiment of the present invention, Fig. 2 is an explanatory diagram of a gas circuit of a rice cooker using this, and Fig. 3
The figure is a perspective view of the flat part 42, and FIG. 4 is an explanatory diagram of a conventional example. Device, 3...operation lever, 4...bimetal switch, 5...pilot safety device.

Claims (1)

[Scope of utility model registration request] A heat-responsive device is used to detect the completion of rice cooking, and the output of the heat-responsive device is used to operate a heating stop means for stopping the heating of the rice cooker A, which is separate from the heat-responsive device. is provided with an over-rise temperature detection means, and this over-rise temperature detection means is
The structure is configured to detect a temperature change proportional to a temperature change in the rice cooking pot, and the output of the over-rise temperature detection means is inputted to the heating stop means, and the set temperature of the over-rise temperature detection means is set higher than the temperature at the time of completion of rice cooking. In addition, an excessive temperature rise prevention device for a rice cooker is set to a temperature corresponding to the internal temperature of the rice cooker that causes edible burnt spots on the rice.