JPS583267Y2 - Induction heating device with top plate crack detection function - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an induction heating device having a top plate crack detection function.

Conventionally, the top plate of an induction heating device is made of a non-magnetic insulating plate such as ceramic, but since a heating container such as an iron or enamel pot is placed on top of the top plate, there is a risk of heat transfer due to the weight of the pot or conduction from the heated container. There is a possibility that cracks may occur due to the heat generated.

If liquid spilled from the pot during cooking enters through the cracks created in this way, it may wet the electrical circuit components inside the heating device, causing electrical leakage, destruction of the electrical components, or risk of electric shock if touched. arise.

In addition, as a conventional top plate and crack detection method, a method is known in which a closed ring circuit is formed on the back surface of the I/tub plate and the disconnection that occurs simultaneously with the cracking of the I/tub plate is detected. The disadvantage of this method is that it cannot detect cracks that occur in areas other than the closed circuit circuit forming area.

The present invention improves the safety of the heating device by detecting the intrusion of moisture into the cracks formed in the top plate and cutting off the power supply.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an L-tube plate made of a non-magnetic insulating plate such as ceramic, on the surface of which is placed a heating container 2 made of a magnetic material such as an iron pot or enamel pot and capable of induction heating.

On the back surface of the top plate 1, two closed-ring electrical circuits A and B made of copper, silver, etc., as shown in FIG.

These two closed loop electrical circuits A and B are each insulated and have two terminals a and l).

3 is a heating coil attached to 1,000 to 1,000 sides of the tube plate.

FIG. 3 shows a circuit diagram, 4 is a commercial AC power supply 5, 5 is a fuse provided at both ends of this AC power supply 4, 6.6 is a power switch provided after the fuses 5, 5. ,
7 is a rectifier circuit, which includes fuses 5, 5 and a power switch 6.
．． It is connected to the AC power source 4 via 6.

8 is a breaker. 9 is a choke coil, 10 is a commutation coil, and 11 is an SCR, which are connected in series to the rectifier circuit 7.

12 is a cover diode connected in antiparallel to 5CR11, and 13 is a commutating capacitor connected in parallel to commutating coil 10 and 5CRII.

14 is a resonant capacitor, and 3 is a heating coil, which are connected in parallel to the rolling contact capacitor 13.

15 is a game l that moves from game 1 to 1 of 5CR11.
- A recovery drive circuit, and the above-mentioned parts constitute an SCR inverter 16.

2 is a heating container. 17.18 is Fuse 5,
A resistor connected in series to the AC power supply 4 via the resistor 5 and the first and second switches 18 are opened and closed in conjunction with the relay 19.

20 is a DC power supply, 21 is a transistor connected in series with the relay 19 between the first and second DC power supplies 20, 22 is a diode connected in parallel with one relay, 23 is
A series circuit consisting of a resistor 24.25 having terminals a, l) is connected in parallel with the relay 19, l--the resistor 21, and the connection potential of the resistor 24.25 is) in addition to the base of the transistor 21. and controls opening and closing of this 11.

A control circuit 26 is constituted by each of these parts.

Next, the operation of the heating device having the above configuration will be explained.

Now, when the device is operating normally, that is, when there is no crack in the l-tube plate 1-1 and no moisture has entered, the terminals a and l) are separated and insulated.

Transistor 21 is therefore in the off state and relay 1
9 is inoperative, switch 18 remains in the intercalary state, and the control device is turned off.

However, if cracks now occur in the top plays 1 to 1 and water enters them, the two closed loop circuits A and B will be short-circuited.

Therefore, the base potential of transistor 21 rises, transistor 21 turns on and operates with relay 19, closing switch 18.

This causes a relatively large alternating current to flow instantaneously through the switch 18 and the resistor 17, causing the fuse 5.5 to
cut.

Here, the value of the resistor 17 is set so that a sufficient current flows to instantly cut the fuse 5.5.

In this manner, control operation 26 operates, and the power supply to rectifier circuit 7 and inverter 16 is cut off.

As shown in L, the induction heating device of the present invention has the top play 1.
・Two separate closed circuit conductors are installed on the back side (1"), which detects a short circuit between both open conductive circuits due to the occurrence of cracks and subsequent moisture intrusion, and turns off the power. It is possible to prevent electrical leakage, destruction of electrical parts, etc. due to moisture intrusion into the device, and it is possible to provide a safe device.

In particular, according to the present invention, the l
・Even if there is a crack in the Tsubu Play 1 part,
If moisture infiltrates from there, it will travel along the back surface of the dowel/tub plate and short-circuit the two closed-circuit circuits, so this crack can be detected at this time.

In addition, the I-tsubu plate is completely broken! If this occurs, the two conductive paths will not be short-circuited and the crack detection function will not work; however, in such a case, no practical problem arises because the device itself can be used.

The device according to this embodiment detects the most dangerous intrusion of moisture when a slight crack occurs in 1-Tububurei River, but does not interfere with the actual heating operation, and at this time, the device can either stop heating or stop. It is possible.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part of the present invention--an embodiment, FIG. 2 is the back side of the tongue plate 1 used on the same side, and FIG. 3 is a circuit diagram of the same side. 1...To the top play river, 2...Heating container, A, B...Closed circuit, 3...Heating coil, 4...・AC power supply, 5.5...
・[News, 6, 6...Power switch, 8
...Breaker, 7...Rectifier circuit, 16
...SCR inverter, 19...Relay, 26...Control circuit.

Claims (1)

[Scope of utility model registration request] A heating coil spirally wound in a plane, a top plate made of a non-magnetic insulating plate disposed on the heating coil-L, and a heating container made of a magnetic material placed on the top plate; In an induction heating device comprising a high-frequency oscillation circuit that supplies high-frequency current to the heating coil, at least two closed-circuit electric circuits are formed close to each other and separated from each other on the back surface of the top plate, and a short circuit of the closed-circuit electric circuit is detected. A control circuit is provided to cut off power supply to the high frequency oscillation circuit, and when the conductive path is short-circuited due to moisture entering a crack formed in the top plate, this is detected and the power is cut off. Induction heating device with top plate crack detection function.