JPS6138013Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dry-burning prevention device for a high-frequency heating device.

A high-frequency heating device uses microwave radio waves to heat and cook food, etc., but if you accidentally operate the high-frequency heating device with no load, the area where the radio waves supplied from the high-frequency oscillator, Magnetro, will be absorbed. If the dry firing (no-load operation) continues for a long time, the life of the magnetron will be significantly shortened, and the magnetron will be damaged. This results in inconvenient conditions for the user, such as melting and breaking the resin structure in the heating chamber. Therefore, the present invention provides a dry firing prevention device for preventing such a situation.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In Fig. 1, 1 is a heating chamber for cooking food, etc., 2 is a magnetron that supplies high-frequency energy into the heating chamber 1, 3 is a door that can be opened and closed to cover the front opening of the heating chamber, 4 is an outer box, Reference numeral 5 indicates a special saucer made of heat-resistant glass or the like, which is placed on the bottom of the heating chamber and on which foods, etc. are placed; and 6, a temperature detection element;
It is provided on the outside of the bottom wall of the heating chamber where it comes into contact.

This invention focuses on the fact that there is a difference in the temperature rise of the saucer 5 when there is food (load) in it and when there is no load, and the saucer 5 is generally made of heat-resistant glass or the like with low high frequency loss. Therefore, if there is food in the heating chamber, most of the radio waves supplied from magnetron 2 will be absorbed by the food, and the
temperature does not rise that much. However, when there is no load, there is nothing in the heating chamber that can absorb radio waves, so the saucer 5 is heated. Therefore, the temperature of the saucer 5 becomes considerably higher than when food or the like is contained therein. Therefore, in the present invention, a temperature detection element is provided on the outside of the heating chamber wall surface that the saucer 5 comes into contact with, and the saucer 5 is
The dry-firing prevention device is configured to detect an abnormal temperature rise in the air conditioner, and when the temperature exceeds a predetermined value, a temperature detection element is activated to stop high-frequency oscillation.

Fig. 3 shows a graph of the time change in the temperature rise value of the saucer 5 during dry firing with respect to the water load 1, which was tested using a high frequency heating device with a high frequency output of 2 KW. As can be seen from Figure 3, the temperature of the saucer changes greatly between when loaded and when unloaded. Therefore, by appropriately setting the operating temperature of the temperature detection element, it will not operate when there is food in it, but will operate when there is no load.
By stopping high-frequency oscillation, a dry firing prevention device can be constructed.

FIG. 2 is a diagram showing an embodiment in which the saucer 7 is of a fixed type, and the saucer 7 made of heat-resistant glass or the like is fixed with a silicone sealant 8 or the like. All other configurations are the same as in FIG. 1, and the same components are designated by the same reference numerals.

As described above, the present invention focuses on the fact that there is a difference in the temperature rise of the saucer that is always attached to high-frequency heating equipment when it is loaded and when it is not loaded, and utilizes this to construct a dry firing prevention device. Because it has a simple configuration, just install a temperature detection element on the outside of the heating chamber wall that the saucer touches, it is possible to provide a dry firing prevention device at a low cost, and even if dry firing occurs by mistake, the life of the magnetron can be shortened. If you do not use it and the high frequency output is high, it may melt the saucer, but this is extremely effective in preventing such damage.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal sectional views of a high-frequency heating device showing an embodiment of the present invention, and FIG. 3 is a graph showing changes in temperature of the saucer with respect to heating time under load and under no load. 1...Heating chamber, 2...Magnetron, 5...Special saucer, 6...Temperature detection element, 7...Saucer, 8...
...Sealing material.

Claims (1)

[Scope of utility model registration request] It has a heating chamber that heats the object to be heated, a high-frequency oscillator that supplies high-frequency energy into the heating chamber, and a saucer made of a dielectric material such as glass that is provided inside the heating chamber and on which the object to be heated is placed. A high-frequency heating device characterized in that a temperature detection element is provided on the outside of a heating chamber wall surface that comes into contact with the heating chamber.