JPS644003Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electric stove using a heater.

Conventionally, as shown in FIG. 1, a charging voltage of a charging/discharging circuit consisting of a resistor 10 and a capacitor 11, which is set to be the heater input power in a steady state, is discharged to a trigger element 12. An electric stove is known in which an AC switching element 14 connected in series to a heater 13 is turned on and off using a trigger pulse.

However, in such electric stoves, the second
As shown in the figure, the heater 13 fills the metal tube 13a with magnesia 13b and the magnesia 13
Since the nichrome wire 13c is wired inside the heater 13b, there is a problem in that it takes a long time for the metal tube 13a to become red-hot under steady-state heater input power, and the rise in temperature of the heater 13 is delayed.

In view of the above-mentioned conventional problems, the present invention aims to provide an electric stove in which the initial heater input power is made larger than the heater input power in the steady state, and the heating time of the heater is shortened. Hereinafter, embodiments of the present invention will be described based on FIGS. 3 and 4 a, b, c, and d.

FIGS. 3 and 4 a, b, c, and d show an embodiment of the present invention, and the same components as those of the conventional example are designated by the same reference numerals. In other words, 10 is a resistor (hereinafter referred to as
Reference numeral 11 (referred to as a first resistor) is a capacitor connected to the resistor 10, and is set so that the electric charge of the capacitor 11 is discharged when the potential of the capacitor 11 reaches a predetermined level. 12 is a trigger pulse 1 which will be described later due to the discharge of the capacitor 11.
Trigger elements forming 2a, 12b (e.g.
SBS), 13 is a heater, and 14 is an AC switching element (for example, a triax) connected in series with the heater 13, which becomes conductive when trigger pulses 12a and 12b are input, and becomes non-conductive at zero potential of the AC voltage waveform. This is set to repeat every half cycle. In addition, 15 is a power adjustment volume connected to the resistor 10, 16 is an AC power supply,
17 is a power switch for the electric stove.

Reference numeral 20 denotes a single-pole double-throw changeover switch operated by a timer 40, which will be described later, with a contact 20a on the power adjustment volume 15 side, and another contact 20b on the second resistor 30 side, which will be described later. Switching contact 20
c are respectively connected to the heater 13 side, and the contact 20a and the switching contact 20c are normally connected.

30 is a second resistor wired in parallel with the first resistor 10 and the power adjustment volume 15,
Set to a resistance value smaller than the first resistor 10,
One end is connected to the capacitor 11 side.

40 is a timer connected to the AC power source 16 via the power switch 17;
After turning on, the changeover switch 20 is controlled so that the other contact 20b and the changeover contact 20c of the changeover switch 20 are connected for several minutes.

In the above configuration, when the power switch 17 of the electric heater is turned on, the timer 40 controls the other contact 20b of the changeover switch 20 to be connected to the changeover contact 20c for several minutes, and the second contact of the charge/discharge circuit is connected. Current is passed through the resistor 30 and capacitor 11. At this time, since the resistance value of the second resistor 30 is set to a small value, the potential of the capacitor 11 quickly reaches the trigger level of the trigger element 12 (11a shown by a solid line), as shown in FIG. 4b. A trigger pulse 12a that rises early in the AC voltage waveform and falls at zero potential as shown in FIGS. 4a and 4c is input from the trigger element 12 to the AC switching element 14. As a result, a large heater input power is supplied to the heater 13.

Further, when several minutes have passed after the power switch 17 is turned on, the changeover switch 20 connects the contact 20a and the changeover contact 20c, and connects the changeover switch 20 through the charge/discharge circuit, that is, the power adjustment volume 15 and the first resistor 10. Current flows to capacitor 11. At this time, the first
Since the resistor 10 has a larger resistance value than the second resistor 30, the potential of the capacitor 11 is triggered at a later time than when the current flows through the second resistor 30, as shown in FIG. 4b. The trigger pulse 12b that reaches the trigger level of the element 12 (11a shown by a dashed-dotted line), rises from the trigger element 12 at a late stage of the AC voltage waveform as shown in FIGS.
4 is input. As a result, heater input power is supplied to the heater 13 in a steady state, which is smaller than that when current flows through the second resistor 30.

As explained above, the present invention is an electric stove in which a trigger element of an AC switching element connected in series with a heater is controlled on and off by the charging voltage of a charging/discharging circuit consisting of a capacitor and a resistor. A small second resistor is connected in parallel with the resistor, and a switch is inserted to switch and connect the resistor and the second resistor to the capacitor, and after turning on the power of the switch,
A timer is provided to control the connection to the second resistor side for a predetermined period of time, so after the power is turned on, current flows to the capacitor via the second resistor with a small resistance value, and the potential of the capacitor quickly decreases. Since the trigger level of the trigger element is reached, a trigger pulse that rises early in the AC voltage waveform from the trigger element is input to the AC switching element, and a large heater input power is supplied to the heater, so that the heating time of the heater becomes faster. This has the advantage of increasing the temperature of the heater quickly.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIG. 1 is a circuit diagram showing the electric circuit of a conventional electric stove, FIG. 2 is a partially cutaway sectional view showing the heater, and FIGS. 3 and 4 a and b. , c, and d show one embodiment of the present invention; FIG. 3 is a circuit diagram showing an electric circuit of an electric stove according to the present invention; FIG. 4 a is a waveform diagram showing an AC voltage waveform; b is a waveform diagram showing changes in the potential of the capacitor, Fig. 4c is a waveform diagram of the trigger pulse when current is passed through the second resistor, and Fig. 4d is a waveform diagram when current is passed through the first resistor. FIG. 3 is a waveform diagram of a trigger pulse. In the figure, 10...Resistor, 11...Capacitor, 1
2... Trigger element, 13... Heater, 14... AC switching element, 16... Power source, 20... Changeover switch, 30... Second resistor, 40... Timer.

Claims (1)

[Scope of utility model registration request] In an electric stove in which a trigger element of an AC switching element connected in series with a heater is controlled on/off by a charging voltage of a charging/discharging circuit consisting of a capacitor and a resistor, a second resistor having a resistance value smaller than the resistance of the charging/discharging circuit is provided. A switch is inserted that is connected in parallel with the resistor and also switches between the resistor and the second resistor to the capacitor, and after the power is turned on, the switch is controlled to be connected to the second resistor side for a predetermined period of time. An electric stove characterized by being equipped with a timer.