JPS6111082B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for a heat insulator for a jar or an electric kettle for use as a jar.In particular, the present invention relates to a temperature control device for a heat insulator for a jar or electric kettle. In other words, the purpose is to shorten the temperature rise time.

Conventionally, when trying to maintain a heat insulator at a constant temperature, there were three methods: a method using a thermostat, a method using phase control, and a method using a zero V switch synchronized with the power supply.

As shown in FIG. 1, there are three control states: A, B, and C. With the method using a thermostat, if the heat response is poor, an overshoot will occur (as shown in A), and if the heat response is good, the problem will be as shown in C, which has the disadvantage that it is difficult to reach the insulating temperature. . Furthermore, the method using phase control often results in the situation shown in (C), and even if improved, it is often difficult to achieve the ideal state shown in (B). Furthermore, in both of the above cases, the equipment generated noise, which sometimes became a social problem. On the other hand, even with the method using a zero-V switch synchronized with the power supply, if there is a large difference in power between energized and de-energized states, overshoot will occur as shown in A. However, discoloration was a problem.

The present invention improves the conventional method described above, reaches a constant heat retention temperature in an ideal short time as shown in (b), and after reaching the heat retention temperature, temperature deviation (temperature ripple) occurs.
The purpose of the present invention is to provide a temperature control device with a small amount of heat.

Examples of the present invention will be described below with reference to FIGS. 2 to 7.

In FIG. 2, 1 is a heater, 2 is a bidirectional control element (hereinafter referred to as a triax), and this series circuit is connected to a power source. 3
supplies a control signal to the gate pole of the triac 2 in the control circuit section. The control circuit section 3 generates pulses synchronized with the AC power supply to switch the triax 2 at zero volts. 4 is a sensor that detects the temperature of the warmer.

FIG. 3 shows the control circuit section 3 in more detail. In FIG. 3, reference numeral 5 denotes a temperature detection circuit, which can be easily constructed from, for example, a differential amplifier, an operational amplifier, or the like. 6 is a transistor, 7 is a zero-volt pulse generation circuit, 8 is a multivibrator, and 9 is a transistor.

As shown in FIG. 4, the zero-volt pulse generation circuit 7 includes a full-wave rectifier circuit 9 composed of diodes,
The protective resistor 10, the resistors 11 and 12 connected between the output terminals of the full-wave rectifier circuit 9, and the resistor 1
1 and 12, and a transistor 13 whose base pole is connected between transistors 1 and 12, and the connection point between transistor 13 and transistor 6 is used as an output terminal.

In the above configuration, when the temperature of the insulator is equal to or lower than the second set temperature t ₁ which is lower than the first set temperature t ₀ , the output of the temperature detection circuit 5 turns on the transistor 6 . By turning on the transistor 6, the zero-volt pulse generation circuit 7 is driven, and the output terminal outputs a pulse (fifth
Figure c) is generated. On the other hand, the multivibrator 8 does not operate when the insulator temperature is lower than the second set temperature _t1 , the transistor 9 is OFF, and the transistor 10 is synchronized with the zero volt pulse from the zero volt pulse generating circuit 7. Turn on the power supply and make the triax 2 100% energized (Fig. 5b). In this state, when the temperature of the insulator reaches or exceeds the second set temperature, the multivibrator 8 also starts operating, the transistor 9 operates according to the energization ratio of the multivibrator 8, and the transistor 10 supplies power to the gain pole of the triac 2. The resulting signal is, for example, 50% (Fig. 5e). Therefore, the energization rate to the heating element 1 is 50% (Fig. 5d). After this, when the temperature of the insulator reaches the first set temperature _t0 or higher, the transistor 6 turns off.
However, the zero-volt pulse generation circuit is not driven, no signal is supplied to the gate pole of the triac 2 (FIG. 5g), and no current is applied to the heating element 1 (FIG. 5f).

After this, if the heat insulator temperature becomes lower than the first set temperature t ₀ , the heating element 1 is energized at a 50% energization ratio, and the above operation is repeated to achieve a control state with less temperature ripple. .

In addition, in the above embodiment, the temperature of the insulator is the first
If the temperature is below the set temperature and above the second set temperature,
The energization ratio may be selected according to the performance of the heat insulator. For example, as shown in FIG. 6, the energization ratio to the heating element 1 may be set to 33%A, 25%B, and 17%C.

As is clear from the above explanation, according to the present invention, the temperature of the insulator quickly reaches the insulating temperature, and even when rice is highly perishable at around 50°C, such as in jiyars, it is possible to prevent the occurrence of rotten odor and keep the temperature low. When stable, the amount of power applied is small, so the width of the temperature ripple is small, and there is no condensation inside the heat insulator, which is of great value.

[Brief explanation of the drawing]

Fig. 1 is a temperature characteristic diagram of a conventional heat insulator, Fig. 2 is a circuit diagram of a heat insulator showing an embodiment of the present invention, Fig. 3 is a circuit diagram of the control circuit of the same circuit, and Fig. 4 is a circuit diagram of the same circuit. FIG. 5 is a signal waveform diagram of the main part of the circuit, and FIG. 6 is a signal waveform diagram when the energization ratio is different. 1... Heater, 2... Triack, 3...
Control circuit section, 4...sensor, 5...temperature detection circuit, 7...zero volt pulse generation circuit.

Claims (1)

[Claims] 1. In a temperature control device such as a heat insulator that controls energization to a heating element by a zero-volt switch circuit that performs a switching operation in synchronization with an AC power source, a second setting in which the temperature of the heated object is lower than the first set temperature If the energization rate to the heating element when the temperature is below the temperature is greater than the energization rate to the heating element when the temperature is within the temperature range of the first set temperature and the second set temperature, and when the temperature is higher than the first set temperature, heat generation occurs. Temperature control devices such as sound holders that reduce the rate of conduction of electricity to the body to zero.