JPS5910483Y2 - Stove - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cooking stove that detects the temperature of food using a temperature detector using a battery power source, and performs control measures such as notification and stopping combustion.

Conventional stoves only have the function of burning, making them inconvenient for actual cooking.

For example, when heating milk for a baby, you need to take the pot off the heat and check the temperature several times.

If the temperature of oil such as tempura oil is raised too high, it will oxidize and become useless.

Even when boiling potatoes, it is common to crush the pot by breaking it.

Cooking is difficult, and the current reality is that housewives manage it with their years of experience and careful attention.

Therefore, it can be imagined that it would be very convenient to add a function to detect the temperature at the bottom of the pot (which is almost the same as the temperature of the food being cooked).In fact, some foreign products have this function, but the temperature accuracy is low. Unfortunately, it is a method that uses commercial power.

Methods that use commercial power are inconvenient because they cannot be used unless there is an outlet nearby, and the power cord can be corroded by oil, acid, or other substances generated from cooking, or depending on the wiring, it can melt due to the heat of combustion. There was a possibility of electrical leakage and fire, and there were problems with installation conditions and safety.

The present invention boosts the dry battery voltage with a switching regulator, uses the boosted voltage to add a temperature control function, and uses the switching to construct a chopper type amplifier, thereby achieving safety and temperature accuracy. This makes it possible to provide an expensive, easy-to-use and convenient stove, and examples thereof will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is the stove body, 3 is a burner, and 2 is a trivet. When a pot is placed on the trivet 2, a temperature sensing portion 4 comes into contact with the bottom of the pot and detects the temperature.

5 is a gas cock and igniter, which ignites the burner 3 by turning it to the left.

6 is a temperature setting dial, and 7 is a notification section.

Its control function will be explained according to FIG.

Reference numeral 8 denotes a dry battery power source, and when the pot 5 is opened, the power switch 9 is closed.

Then, the oscillator 10 operates, and the booster circuit 11, which together with the oscillator 10 forms a switching regulator, increases the dry battery voltage to the target voltage.

Reference numeral 13 denotes a chopper type amplifier, which chopper-amplifies the temperature signal using the output of the oscillator 10, so that offsets and temperature drifts of the control circuit are all ignored, allowing highly accurate amplification.

15 is a comparator that compares the temperature amplification signal with the signal from the temperature setter 14, and at the moment the temperature signal becomes higher than the set value, it activates the OFF delay timer 16 and maintains a constant value until the timer 16 turns OFF. time (e.g. 5 seconds) buzzer 17
The device makes a sound to notify the user that the food has reached the set temperature.

FIG. 3 shows an embodiment of this control circuit.

8 is a battery, 9 is a switch, 17 is a buzzer, 14' is a temperature setting volume, and 12 is a temperature sensor (thermo couple in this example).

18, 33.40 is an open collector comparator,
46 indicates an operational amplifier.

First, when the switch 9 is turned on in conjunction with the cock, the transistor 35 oscillates, and when turned on, energy is stored in the inductance 37, and when turned off, the energy is charged to the capacitor 36 via the diode 38 and boosts the voltage.

Next, the oscillation operation of the transistor 35 will be explained.

The capacitor 29 is charged through the resistor 24, and the resistor 2
5. At the moment when the voltage rises above the voltage divided by 30, the comparator 33 becomes ONL, the charge of the capacitor 29 becomes the resistor 31,
Discharge begins via the diode 32.

At this time, a resistor 26 and a diode 27 are connected in parallel with the resistor 30, and the reference potential is lowered.

The moment the potential of the capacitor 29 falls below the reference potential, the comparator 33 turns OFF, and oscillates repeatedly.

When the comparator 33 is ON, the base current of the transistor 35 is not supplied and is in the OFF state, but when the comparator 33 is OFF, the base current is supplied to the transistor 35 via the resistors 28 and 34. Turn on.

That is, it is inverted in synchronization with the comparator 33 and turned on and off.

The boosted voltage is maintained at a constant voltage by three resistors and a Zener diode 56.

Next, the amplification of the temperature signal will be explained.

The reference voltage of the operational amplifier 46 is set at the resistor 53 within the constant voltage.
,54. 55.

The electromotive voltage of the temperature sensor is a resistance 48. It is increased in accordance with the degree of increase obtained by the ratio of resistance 49 and resistance 47,
Since the field effect transistor 50 turns ON and OFF in synchronization with the comparator 33, by designing the value of the resistor 49 to be larger than the resistance between the drain and source when the transistor 50 is ON, AC modulation is carried out and the voltage is applied to the primary side of the transformer 45. applied.

Since only the alternating current component is transmitted to the secondary side of the transformer 45, the offset and temperature drift components of the intensifier are set, and an alternating current signal proportional to the pure temperature signal is obtained.

The AC component on the secondary side is turned on and off in synchronization with the transistor 35.
The signal is demodulated into a DC voltage by a field effect transistor 42 that turns FF and a capacitor 43.

The temperature setting potential is also a resistor 41 connected within a constant voltage.
．． 44 and volume 14', and can be freely changed depending on the position of the volume.

A thermistor 52 compensates for the cold junction temperature of the sensor 12.

When the burner is ignited, the sensor temperature is lower than the set temperature, so the comparator 40 is OFF.

Since the input potential (1) of the comparator 18 is maintained at the dry battery voltage (2) by the resistor 23, it is higher than the reference potential divided by the resistors 19 and 20, and therefore remains OFF.

At the moment when the temperature of the food to be cooked rises and exceeds the set temperature, the comparator 40 turns ON, and the ■ input potential of the comparator 18 also falls below the ○ input potential, so the comparator 18 also turns ON.
Then, the buzzer 17 is activated to notify the user that the set temperature has been reached.

From this moment, charging of the capacitor 22 is started via the resistor 21, and after a certain period of time (for example, 5 seconds), when the input potential increases above the input potential, the comparator 18 is turned off and the buzzer is turned off.

Above, an example was shown in which the buzzer 17 is used to notify when the set temperature is reached, but FIG. 4 shows an example in which the buzzer is used to notify and at the same time the gas is shut off.

This figure shows a part of FIG. 3, and the same numbers indicate the same functions.

57 is a gas valve coil, and the valve is connected between the cock and the burner (not shown).When the detected temperature is lower than the temperature setting, it supplies the base current of the transistor 59 through the resistor 23.61. , turn on.

The value of the resistor 61 is sufficiently larger than that of the resistor 21.23 so as not to interfere with the timer operation.

60 is the base-emitter resistance of the transistor 59, 58
is for absorbing back electromotive force of the coil 57.

Combustion continues in this state, and when the set temperature is reached and the comparator 40 is turned on, the transistor 59 is turned off, deenergizing the gas valve coil 57 to cut off combustion, and alerting with the buzzer as described above.

As mentioned above, this invention uses a shared oscillator to boost the battery voltage and chop the temperature signal, so it is possible to use a dry battery power source while significantly reducing the number of circuit components. The function can be greatly improved without worrying about electrical leakage and fire, regardless of the installation location, and the accuracy of temperature detection itself has been improved, allowing cooking without failure.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a stove showing an embodiment of the present invention, Fig. 2 is a control block diagram, Fig. 3 is a specific circuit diagram thereof, and Fig. 4 is a perspective view of a stove showing an embodiment of the present invention.
The figure is a circuit diagram in another embodiment. 8... Battery, 10... Oscillator, 11.
. . . Boost circuit (combined with oscillator 10 to form a switching regulator), 12 . . . Temperature sensor, 13
... Chotupa type amplifier.

Claims (1)

[Scope of utility model registration request] A temperature sensor placed at a position to detect the temperature of a cooking container installed on the stove, a battery for driving a control circuit, a switching regulator for boosting the battery voltage, and an oscillator for converting the temperature signal detected by the sensor into a switching regulator. A stove consisting of a chopper amplifier that is used for chopping in common, and a control circuit that compares the amplifier signal with a set value and performs control measures such as cutting off combustion or performing a warning operation for a certain period of time.