JPS5829025A - Controller for heat cooking apparatus - Google Patents

Abstract

PURPOSE:To decrease the time reaching a set temperature, by heating with a maximum combustion amount until the temp. attains a set temperature when a difference between the set temperature and a temperature sensor is a specified value or over, and performing proportional control afterward. CONSTITUTION:In a heating cooking apparatus, when a temperature of a temperature sensor 2 under a pan 1 and a set temperature 4 are a specified set value >=9 in the difference, a storage circuit 8 outputs a drive signal to a storage circuit 10. The circuit 10 outputs a signal keeping the maximum combustion amount of a burner 6 independently of the temperature of the temperature sensor 2 to a comparison amplifier 3. When the temperature of the temperature sensor 2 is equal to the set temperature, the circuit 8 outputs a signal releasing the keeping of the amount to the circuit 10 and the amplifier 3 controls a proportional valve 5 to the burner combustion amount in response to the difference between the temperature of the sensor 2 and the set temperature. Thus, when the temperature is lower than the set value at the start of heating, the time reaching the set value can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating cooker that maintains the temperature of the food at a constant level by continuously varying the heating amount, and the present invention relates to a heating cooker that maintains the temperature of the food at a constant level by continuously varying the amount of heating. It is an object of the present invention to provide a control device configured to shorten the time it takes for an object to reach a set temperature.

Conventionally, automatic temperature control type cookers have been developed for reasons such as automation of cooking, safety, and energy saving. Fourth
The figure is an example of a gas staple stove VC I+.
In this example, the bottom temperature of the pot 1 is detected by the temperature sensor 2, and compared and amplified with the set temperature 4 by the comparison amplification circuit 3, thereby driving the proportional valve 6 that continuously varies the gas amount. Thereby, the combustion amount of the burner 6 is controlled to a value according to the temperature sensor 2 and the set temperature 4. 7 indicates a manual cock.

The combustion amount gradually decreases (in the Y region of the figure, when the sensor temperature reaches the set temperature D1, the combustion amount becomes L2, and the burner 6 is set to the minimum combustion amount that allows safe combustion. Therefore, even if the temperature rises further, the proportional valve 5 will not be throttled down and will maintain the combustion amount L1 (Z area in the figure).In addition to this, there is a case where the temperature set value D1 is set to the midpoint of the Y area, etc. or,
Increase by driving the valve in the Z area. As shown below, the amount of combustion is increased or decreased to keep the temperature at the bottom of the pot constant.

This time chart is shown in FIG. 6 and FIG. 7, where the horizontal axis T is time, the vertical axis is temperature, and L is the combustion amount.

Further, characteristic A in the figure shows the case where the proportional control shown in FIG. 4 is performed, and characteristic B shows the characteristic when the burner 6 is always at maximum combustion without performing the control.

Now, if the burner 6 is ignited at time T0, the burner burns at its maximum in the region X of FIG. 6 until the temperature rises and reaches time T1, and characteristics A and B do not change.

Next, when the Y range is reached, characteristic A starts to reduce the combustion amount and reaches the set temperature at time T2, as shown in FIG.

At this time, as shown in FIG. 6, since the combustion amount is not reduced in characteristic B, the temperature reaches the temperature D1 determined at time T2', but the temperature continues to rise. In this case, characteristic A immediately increases the combustion amount and returns to the set temperature D1. However, in characteristic B, after the temperature drops once, the temperature further rises by -F.

This occurs when the amount of combustion is reduced as the temperature approaches the set temperature.

In addition, if the food inside the pot 1 is a simmering dish with a lot of water, the set temperature D1 needs to be set to 100"C. At this time, if the set temperature exceeds 100"C due to variations in the set temperature, the τ pattern Since the temperature of the parts never exceeds 100"C (because water boils at 100°C), the set temperature will not be reached forever, and there is a risk that the amount of combustion will not be reduced and scorching will occur. For this reason, the temperature is 100°C for safety.
If you set it to a lower value, the amount of combustion will be reduced quickly, so it will take longer to reach the set temperature, so if there is a problem with cooking, heat at the maximum amount of combustion until the set temperature is reached, and then perform proportional control. As a configuration, it is possible to shorten the above-mentioned rise time delay.

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

Since the difference between the temperature and the set temperature 4 is predetermined, the burner combustion is controlled according to the difference between the temperature of the first set 2 and the set temperature.

Reference numeral 11 indicates a controller including the above circuit.

Figure 2 shows its operating characteristics, with temperature on the horizontal axis and L1 on the vertical axis.
shows the combustion amount. The characteristic ζ1 shown by the solid line in the figure is a proportional control characteristic similar to that shown in FIG. Here, the temperature storage circuit 8 memorizes this, and the maximum combustion amount is maintained by the holding circuit 1o. Therefore, even in the Y range, as shown by the broken line in the figure, the maximum combustion amount is still 1υ11. When the 3° sensor temperature reaches the set temperature D1, the hold 1, \ circuit 1o is released and the normal proportional control characteristic ( solid line).

FIG. 3 shows a concrete example of the circuit. Reference numeral 12 is a DC power supply that supplies power to the controller through a switch 13 interlocked with the cock 7.

A bridge circuit is constructed by the temperature sensor 2 (an example using a negative temperature sensitive resistance element), the temperature setting variable resistor 4, and the resistor 14°15.16, and the midpoint potential d is connected to the operational amplifier 18 through the resistor 17. 6 is connected to the negative input terminal, and 6 is connected to the positive input terminal.

The operational amplifier 18 constitutes an inverting amplifier circuit with resistors 17 and 19, and its output is connected to the base of a transistor 21 through a resistor 20.

The emitter of the transistor 21 is connected to the negative input terminal of the operational amplifier 18 through a resistor 19 and to the power supply 1 through a resistor 22.
They are each connected to the No. 2 O line.

Further, the collector of the transistor 26 is connected to the line (2) of the power source 12 through the proportional valve 5. Here, an example is shown in which the proportional valve 6 is an electromagnetic gas proportional control valve configured to continuously vary the gas flow rate in accordance with the current flowing through the electromagnetic coil. 23 is a protection diode for absorbing the back electromotive force of the coil of the proportional valve 5, and 24 is the base resistance of the transistor 210.

Here, the current value I flowing through the proportional valve 6 is determined by the following equation.

Therefore, I at this time increases. Conversely, when the temperature of the sensor 2 is high, the potential a increases and the potential I decreases. Potential a
= b indicates that the sensor temperature has reached the set temperature. Here, if the setting variable resistor 4 is increased, the resistance of the sensor 2 will decrease by the increase in the variable resistor until the potential a = b, which corresponds to an increase in the set temperature by that amount. do.

Further, the potential a is also connected to the negative input terminal of the operational amplifier 26, and the positive input terminal is connected to the b voltage potential C of the resistors 26 and 27, and is also connected to the output terminal through the resistor 28 and the diode 29.

Further, the output terminal of the operational amplifier 25 is connected to the positive input terminal of the operational amplifier 18 through a diode 30. Here, since the operational amplifier 25 operates as a comparator, it will be referred to as a comparator hereinafter. The resistors 26 and 27 are designed so that the potential b = c when the comparator 26 has a high output, that is, when the diode 29 is reverse biased. Further, the potential C is stored until the resistor 28 and diode 29 are connected in parallel with the resistor 17 and the potential b>c' and the preset temperature is reached when the output of the comparator 26 is low. In addition, since the output of the comparator 26 becomes high (approximately the same as the potential of the power supply), the potential is also high through the diode 3o, and the output of the amplifier 18 becomes high when the high temperature sensor 2 reaches the set temperature (d2) regardless of the potential a. C) Since the comparator 26 has a low output and the diode 30 is reverse biased, the current 1 is controlled to a value corresponding to the potential difference between the potentials a and b.

Furthermore, even if the temperature drops due to the addition of material to the pot 1 during control, if the temperature drop is small and the potential d'·C' is present, the comparator 26 will not be inverted and the normal proportion will be maintained.

FIG. 8 shows another embodiment. This is especially true when there is a lot of moisture inside the food, such as when stewing, etc.
If there is a variation even slightly larger than 0°C, the set temperature will not be reached forever and combustion will continue, so there is a risk of burning. This problem can be solved by setting the temperature a little lower in advance, but I don't do that.

Therefore, in FIGS. 8 and 9, when the sc storage circuit 8 is operating, the holding circuit 1o is held at the maximum combustion amount in the Y region, and when the set temperature D1 is reached, the second When the set value 31 (D3-Dl) is exceeded, the storage circuit 8 releases the holding circuit 10.

With the above configuration, even if the set temperature D1 is set slightly lower than 100"C, even after the set temperature D1 is reached, heating will be performed at the combustion amount L3 until a certain temperature rise occurs, so the combustion will suddenly occur. The rise time is shorter than when the amount is reduced to L2.

FIG. 10 shows an example of this specific circuit.

When the outputs of the operational amplifier 34 and the comparator 26, which operate as comparators, are high outputs (because the temperature of the diode 29.2 is low, the potential C current across the resistors 26, 32, and 33 is the potential a of the resistor 32. 33, resistor 28 and diode 29
are connected in parallel.

d', and the comparator 25 becomes a high output.
When the temperature of rises and reaches the set temperature (potential a=
c) The output of the comparator 34 becomes low and the potential at the point where the output of the amplifier 18 is combined with the resistor 20 and 20' is lowered through the resistor 36 and the diode 37. At this time, the amplifier 18 is set to the maximum value of the proportional valve by the comparator 25. An output that conducts current is output, but when it is biased by the resistor 36 and the current value of the proportional valve reaches the second value (D3 in Figure 9), the comparator 25 becomes a low output and reverse biases the diode 30. Clear memory. As a result, the negative input terminal F- of the comparator 34 also becomes a low potential through the diode 38, so the comparator 34 outputs a high output and reverse biases the diode 37. From the above, the proportional valve 6 controls the combustion amount according to the difference between the potentials a and b. This is a positive feedback resistor for stabilizing the operation of the 39ii comparator 34.

In this embodiment, a gas burner is used as the heating device, but an electric heater or the like may also be used. In addition to table stoves, it can also be applied to open stoves.

The structure shortens the time it takes to reach the set value when the temperature drops significantly below the set temperature, which shortens the time required to complete the product and improves usability. Furthermore, since the food is heated all at once with the maximum amount of combustion until it reaches the set temperature, less heat is radiated from the food, improving combustion efficiency.

Furthermore, by providing a circuit that switches the value to maintain the combustion amount at a point between strong and weak until the set temperature is reached and the temperature rises to a certain temperature -F, it is possible to When setting to 'OO°C, due to variations in the high temperature side of the set temperature, the set temperature may not be reached forever and the heating continues with strong combustion.In this case, the set temperature is also heated with a constant combustion lid, so the time to reach boiling can be shortened. It is measured.

It is an industrial value with such various effects.

[Brief explanation of drawings]

Fig. 1 is a control system diagram of the control device for the heating cooker of the present invention, Fig. 2 is its characteristic diagram, and Fig. 3 is its specific circuit diagram.
Figure 4 is a control rjll system diagram of a conventional proportional control circuit.
Figure 6 is its characteristic diagram. Fig. 7 shows the time chart at the start of combustion of the system shown in Fig. 4, Fig. 8 is a control system diagram showing another embodiment of the present invention, Fig. 9 is its characteristic diagram, and Fig. 10 is its specific circuit. It is a diagram. 2. Temperature sensor (temperature detector), 3... Comparative amplifier, 4... Temperature setting value (temperature setting means), 5...
...Proportional valve (control means), 6--Burner (heating stage), 8--Memory circuit, 9--Predetermined /B'
j First set value, 1o... Holding circuit, 11... Controller, 32-... Predetermined second set value, 1 Name of agent Patent attorney Toshi Nakao and 1 other person Figure 4 Figure 6 // Figure 7 Th TH+2 13

Claims (1)

[Scope of Claims] 1) A heating means for heating the food, a temperature detector for detecting the temperature of the food, and a heating amount of the heating means according to a signal from the temperature sensor. and a controller that compares and processes the signal of the temperature sensor and the signal of the temperature setting means and supplies the signal to the control means, and the controller has a built-in comparison and amplification circuit. and a memory circuit that stores this when the difference between the temperature signal detected by the temperature sensor and the set temperature of the temperature setting means exceeds a predetermined first set value; A control device for a heating cooker configured to drive a holding circuit that keeps a control amount of a control means constant. 2) Control of the heating cooker according to claim 1, wherein the storage circuit is configured to release the drive of the holding circuit when the temperature signal detected by the temperature detector and the set temperature of the temperature setting means become equal. Device. 3) The holding circuit is configured to switch the control means to hold the second control amount when the temperature signal detected by the temperature sensor and the set temperature of the temperature setting means become equal, and the storage circuit is configured to switch the control means to the second control amount when the temperature signal detected by the temperature detector becomes equal to the set temperature of the temperature setting means. Claim 1(d): Cooking by heating, wherein the drive of the holding circuit is released when the detected temperature signal exceeds the set temperature of the temperature setting means by a predetermined second set value. device control device.