JPS6038422Y2 - electric cooker - Google Patents

Description

[Detailed explanation of the idea] This invention relates to improvements in electric cookers.

Examples of electric cookers include electric pressure cookers and electric rice cookers, but conventionally, with such cookers equipped with a heat-retaining heater, electricity can be turned on to the heat-retaining heater simply by setting the pot in the cooker itself. For example, when cooking rice, if water is left in the rice for a long time, the rice will become half-cooked.

For this reason, if you want to leave water in it for a long time, you have to unplug the W cord from the outlet, which makes it inconvenient to use.

This idea was devised to eliminate these drawbacks; even if a cooking pot is placed in the cooking device, the power to the warming heater will not start unless the power switch is turned on, and cooking will not start. To provide an easy-to-use electric cooker capable of automatically stopping power supply to a heat-retaining heater when a cooking pot is removed from a cooker body after cooking.

Hereinafter, embodiments of this invention will be described with reference to the drawings.

In this embodiment, this invention will be described as applied to an electric pressure cooker.

FIG. 1 is a cross-sectional view showing the overall structure, where 1 is the podium and 2 is the inner frame, which form the main body of the cooker.

A space having a U-shaped cross section is formed between the body 1 and the inner frame 2, and a heat insulating material 3 is filled in the space surrounded by the side surfaces of the body 1 and the inner frame 2, and A frame 4 is attached to the opening above the entire space.

A cord-shaped heat insulating heater 5 having a relatively small heat generating capacity is wrapped around the outer surface of the inner frame 2, and a thermal reed switch 6 is attached thereto.

On the outer surface of the body 1 are an automatic return type push-type power switch 7, a cooking lamp 8, a steaming lamp 9, and a warming lamp 1.
0, the operating devices 12 each having a cooking knob 11 attached thereto are attached.

The cooking knob 11 is fixed to an operating shaft of a cooking time setting timer 13 provided in the space, and is used to set the cooking time.

In a space surrounded by the lower surface and bottom surface of the body 1 and the bottom surface of the inner frame 2, an appliance plug 14 for inserting a power plug and an electric circuit storage portion 15 are provided fixed to the body 1 side. A set switch 16 is also fixedly provided on the inner frame 2 side.

The electric circuit storage section 15 stores various circuit components to be described later, and a heat plate 17 is attached to the upper part of the storage section 15, and ventilation holes 18 are formed at the lower part.

Legs 19 are attached to the outside of the bottom surface of the body 1.

A circular recess 20 is formed in the center of the bottom surface of the inner frame 2, and a cylindrical pot detection member 22 that is vertically movable and is always urged upward by a spring 21 is provided in the recess 20. ing.

A switch operating lever 23 is attached to the lower part of the pot detecting member 22, and when the member 22 is pushed down against the biasing force of the spring 21, the operating lever 23
3, the set switch 16 is turned on.

A negative characteristic thermistor 24 is fixed inside the upper surface of the pot detection member 22 as a temperature detection element.

A sheathed heater 25 is also attached to the periphery of the bottom of the inner frame 2 so as to surround the recess 20 as a heating element for cooking with a relatively large heat generating capacity.

A cooking pot 27 having handles 26, 26 attached to its peripheral edge is housed inside the inner frame 2.

A pressure regulating mechanism 28 is installed approximately at the center of the upper opening of the cooking pot 27, and a safety valve 29 that opens due to abnormal pressure is installed, and a packing material 30 is installed at the periphery.
The peripheral edge of the lid body 31 to which the lid body 31 is attached is held in a recess formed in the handle 26 of the pot 27 to seal the pot 27 tightly.

The pressure adjustment mechanism 28 includes a nozzle opening 32 that passes through the lid 31 and a pressure adjustment valve 33 that closes the upper part of the nozzle opening 32 by its own weight.

A handle 34 is attached to the outside of the lid 31.

FIG. 2 shows a control circuit for the appliance plug 14.
One terminal of the current fuse 35, temperature fuse 36,
The set switch 16 and the power switch 7 are connected in series to the line 1□, and the plug 1
The other terminal of 4 is connected to line 1°.

The first as a reset relay is connected between the lines 11 and 1°.
The relay 37 is connected and the sheathed heater 25 is connected.
and a first bidirectional three-terminal thyristor 38 as a semiconductor switching element are connected in series.

A protective varistor 39 is connected between both terminals of the plug 14 via the current fuse 35.

A normally open contact 37m of the first relay 37 is connected to the power switch 7 in parallel.

Further, a series circuit of the heat insulating heater 5 and the thermal reed switch 6 is connected between the lines 11 and 1□ via the normally closed side of the switching type second timer contact 40, and the second
The cooking timer 1 is connected to the cooking timer 1 through the normally open side of the timer contact 40 of the
A series circuit of the No. 3 timer motor 41 and the second bidirectional three-terminal thyristor 42 is connected.

The heat retaining lamp 10 is connected in parallel to the series circuit of the heat retaining heater 5 and the thermal reed switch 6, the second relay 43 is connected in parallel to the timer motor 41, and the second thyristor 42 is connected to the second relay 43 in parallel. The normally open contacts 43m of the second relay 43 are connected in parallel.

Furthermore, the steaming lamp 9 is connected in series between the lines 1□ and 1° through the normally open side of the second timer contact 40 and the normally closed side of the switching type first timer contact 44. The cooking lamp 8 is connected in series through the normally open side of the second timer contact 40 and the normally open side of the first timer contact 44.
and a temperature control circuit 45 as a heating element control circuit for cooking.
are connected.

The thermistor 24 is connected to the temperature control circuit 45, and the gates of the thyristors 38 and 42 are also connected.

The timer motor 41 operates the first motor at a required timing.
．． This is to switch and control the second timer contact 44.40, and when the cooking time is not set, both timer contacts 44.4
0 is set to the normally closed side, and when the cooking time is set, both timer contacts 44 and 40 are set to the normally open side, and when the required actual cooking time has elapsed, the first timer contact 44 is switched to the normally closed side to steam the steam. The time is set, and when a certain steaming time has elapsed, the second timer contact 40 is switched to the normally closed side, and both timer contacts 44 and 40 are returned to their original states.

The temperature control circuit 45 maintains the internal temperature of the pot 27 detected by the thermistor 24 at a stable temperature during cooking (for example, 11
When the temperature reaches a temperature slightly lower than 0° C. (for example, 100° C.), the first swivel resistor 38 is switched from full-wave conduction control to half-wave conduction control using well-known means, and the internal temperature of the pot 27 becomes stable. When this temperature is reached, the first thyristor 38 is turned ON-OFF under half-wave conduction control to keep the internal temperature of the pot 27 substantially constant at a stable temperature.

Further, the temperature control circuit 45 controls the timing when the internal pressure of the pot 27 increases depending on the internal temperature of the pot 27 (when the temperature reaches 100%).
The second thyristor 42 is controlled to be conductive at a timing when the temperature reaches close to .degree.

Next, the operation of the apparatus according to the embodiment of the present invention constructed as described above will be described based on the timing chart of FIG.

When the food to be cooked is placed in the pot 27 and stored in the inner frame 2 at (■) in FIG. 3, the pot detection member 22 is pushed down by the weight of the pot 27 against the biasing force of the spring 21. The set switch 16 is turned on.

Next, attach the lid 31 to the handle 26, 26 of the pot 27 by attaching its peripheral edge to the lid 31.
Set it by holding it in the recess.

In this state, the power plug is inserted into the appliance plug 14 as shown in FIG. 3, and the desired cooking time is set using the cooking knob 11.

This leads to the first. The second timer contacts 44, 40 are set to close the normally open side.

This puts it on standby.

Therefore, when the power switch 7 is turned on at ■ in Figure 3, the first
The relay 37 is energized and its normally open contact 37m is closed.

Thereafter, the first relay 37 is self-held even if the power switch 7 is reset.

On the other hand, when the power switch 7 is turned on and the normally open contact 37m of the first relay 37 is closed, power supply to the temperature control circuit 45 and the cooking lamp 8 is started.

Then, first, the first thyristor 38 is controlled to be in full-wave conduction by the temperature control circuit 45, and the sheathed heater 25 starts a heating operation with relatively large supplied power.

This is point ■ on the temperature curve ■ shown in FIG.

In this way, the pot 27 is heated and the internal temperature of the pot 27 increases with a rapid rising characteristic.

When the inside of the pot 27 eventually reaches the boiling point, the internal pressure of the pot 27 begins to rise.

This is the point ◎ on the pressure curve @ shown in FIG.

Further, the internal temperature of the pot 27 rises and reaches 100° C., which is slightly lower than the stable temperature (110° C.) at point 3 in FIG.

(point 0 in FIG. 4) and the temperature detection output of the thermistor 24, the temperature control circuit 45 switches the first thyristor 38 from full-wave conduction to half-wave conduction control.

In this way, the sheath heater 25 now starts its heating operation with a relatively small supply power of about half, and the internal temperature of the pot 27 changes from the previous rapid rise to a relatively gradual rise.

Further, the temperature control circuit 45 controls conduction of the second thyristor 42 .

As a result, power supply to the timer motor 41 is started, and the second relay 43 is energized, and its normally open contact 43m is energized.
Close.

Thereafter, the timer motor 41 and the second relay 43 are kept energized by closing the normally open contact 43m.

Then, when the internal temperature of the pot 27 further increases and reaches the stable temperature of 110°C at the 0 point in FIG.
The thyristor 38 is controlled to be non-conductive.

In this manner, from then on, when the internal temperature reaches a stable temperature, the first thyristor 38 is controlled to be non-conductive by the temperature control circuit 45, and when the temperature falls below the stable temperature, the first thyristor 38 is controlled to be half-wave conductive, and the internal temperature of the pot 27 is Cooking proceeds while maintaining the temperature at a substantially stable temperature.

On the other hand, when the internal pressure of the pot 27 increases and the gauge pressure exceeds 1 kg/cr# at point [F] in FIG.
opens to release steam and keep the internal pressure approximately constant at 1 kg/cr&.

When the required actual cooking time has elapsed, the first timer contact 44 opens the normally open side and closes the normally closed side at point (3) in FIG. At the same time as the steaming lamp 9 is stopped, electricity supply to the steaming lamp 9 is started.

(Point [F] in FIG. 4) In this way, the electricity supply to the sheathed heater 25 is completely stopped, and the internal temperature and internal pressure of the pot 27 begin to gradually decrease due to natural cooling, and the steaming operation is started.

Then, the internal pressure of the pot 27 is surely Okg/cr/r.

(point 0 in FIG. 4), the second timer contact 40 switches from the normally open side to the normally closed side, and the output to the timer motor 41, second relay 43, and steam lamp 9 is At the same time as the electricity supply is stopped, electricity supply to the warming lamp 10 is started and the steaming operation is switched to the warming operation, the cooking operation is temporarily finished, and the food to be cooked in the pot 27 can be taken out at any time thereafter.

This is 0 in FIG. The internal temperature of the pot 27 further decreases to, for example, 70°C at ■ in Figure 3 (■ in Figure 4).
) and the thermal reed switch 6 are closed and the insulation heater 5 is closed.
energization starts.

Thereafter, the heat-retaining heater 5 is controlled to be turned on and off by opening and closing the thermal reed switch 6, and the internal temperature of the pot 27 is kept constant at approximately 70°C.

In this state, when the cooking pot 27 is removed from the inner frame 2 by the handles 26, 26, the set switch 16 is opened, the first relay 37 is deenergized, and its normally open contact 37m is opened.

In this way, power supply to the heat-retaining heater 5 is automatically stopped.

Thereafter, even if the pot 27 is reset into the inner frame 2, the power to the heat-retaining heater 5 will not be re-energized unless the power switch 7 is turned on again.

The above is the effect when operating normally, but with such a device, if the internal temperature of the pot 27 rises abnormally for some reason, as shown in [F] in Figure 4, it can become extremely dangerous. Become.

At this time, the bilimiter provided in the temperature control circuit 45 operates at the 0 point (for example, 125 DEG C.) in FIG. 4 to forcibly control the first thyristor 38 to become non-conductive.

If the temperature continues to rise further, the temperature fuse 36 blows at point [F] (for example, 130° C.) in FIG. 4, cutting off the power supply to the circuit.

Furthermore, if the nozzle 32 becomes clogged or the like and the internal pressure of the pot 27 rises abnormally as shown by M in FIG. 4, an extremely dangerous situation will occur.

At this time, for example, the internal pressure is a stable pressure of 1 kg/a+!
The safety valve 29 operates at the 0 point in FIG. 4, which is twice the value of , and releases steam.

Even if the cooking pot 27 is set in the inner frame 2 in this way and the power plug is inserted into the appliance plug 14, the heater 5 will not be energized unless the power switch 7 is turned on and the first relay 37 is energized. Never.

Therefore, even if the cooking pot 27 is set in the inner frame 2 and left for a long time with the power plug inserted into the appliance plug 14, the food in the pot 27 will not become half-cooked.

Then, by setting the cooking time with the cooking knob 11 and turning on the power switch 7, cooking is reliably started, and after the cooking is finished, power supply to the heat-retaining heater 5 is started.

Further, by removing the cooking pot 27 from the inner frame 2, the power supply to the heat-retaining heater 5 is automatically stopped.

In this way, ease of use as a cooking device can be improved.

In addition, although the above-mentioned embodiment described the application of this invention to an electric pressure cooker, it is not necessarily limited to this, and can be applied to an electric rice cooker, etc.

As detailed above, according to this invention, even if the cooking pot is set in the cooking device, the power to the warming heater does not start, and the power to the warming heater is not turned on after cooking is finished. If the cooking pot is removed from the cooker body while the cooking pot is being heated, power to the heat-retaining heater is automatically stopped, so it is possible to provide an electric cooker that is easy to use and has improved practicality.

[Brief explanation of drawings]

The figures show an embodiment of this invention: Figure 1 is a sectional view, Figure 2 is a control circuit diagram, Figure 3 is a timing diagram showing the operation timing of each part in Figure 2, and Figure 4 is the inside of the pot. It is a graph showing temperature characteristics and internal pressure characteristics. 1...Body, 2...Inner body, 5...
...Heat insulation heater, 7...Power switch, 1
6...Set switch, 25...Seed heater, 27...Cooking pot, 37...
First relay, 38...First bidirectional three-terminal switch, 40, 44...Timer contact, 41
...Timer motor, 45...Temperature control circuit.

Claims (1)

[Scope of utility model registration request] A cooking pot removably attached to the cooker body, a set switch that responds to the setting of the cooking pot to the cooker body, a timer for setting cooking time, and a press of the set switch and automatic return type at W. A reset relay connected in series with a power switch, a normally closed contact of the reset relay connected in parallel with the power switch, and a set switch, a power switch, and a semiconductor switching element connected in series with the power supply. a cooking heating element that heats the cooking pot with a relatively large amount of power; a cooking heating element control circuit that controls conduction of the semiconductor switching element when a cooking time is set by the timer; and the set switch connected to the power source; An electric cooker comprising a power switch and a heat-retaining heater that is connected in series with a normally closed contact that is closed when the timer is not set, and that heats the cooking pot with a relatively small amount of electric power. .