JPS6216715A - Boiling detector in rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a method for obtaining a boiling detection signal when water in a pot is in a boiling state (tffi = ), and using this boiling detection signal for rice cooking control. The present invention relates to a boiling detection device for a rice cooker.

[Technical background of the invention and its problems] In recent rice cookers, various rice cooking controls are used. Specifically, for example, when cooking white rice, the rice cooking heater is turned on only until the water in the steel boils. By generating heat using human power, the well-known rice can be cooked deliciously.''It satisfies the so-called ``medium-pattupa'' condition, which is one of the conditions for gerudame, and boils II! ! Afterwards, the heater output is reduced to prevent the rice from burning, thereby making the rice more delicious. Controls are being implemented to prevent boiling over by reducing the output of the steel, but when performing such control, it is necessary to detect whether or not the water in the steel has reached a boiling state.1 However, in conventional rice cookers, the temperature of the pot is detected, and when the detected temperature reaches a predetermined upper limit temperature, this is done. lIi
The most common method is to judge the state of
In this case, in order to accurately detect the boiling state, it is desirable to set the reference humidity to near 100'C. However, if this J: sea urchin = limit temperature is set near 100°C, the contact state between the temperature sensor section and the steel for detecting the steel wetness, and the circuit constant of the temperature sensor section. Even if the inside of the steel is in a boiling state due to variations in the temperature and changes in its characteristics over time, changes in atmospheric pressure, or fluctuations in the boiling point due to the amount of seasoning added to the steel when making cooked rice, etc. However, the boiling state may not be detected no matter how long it takes, and in reality, the upper limit temperature is set at around 80°C in anticipation of such fluctuations.

For this reason, the conventional boiling detection device has a problem in that the detection of the boiling state in the steel is extremely inaccurate, and as a result, it becomes impossible to accurately control rice cooking by the rice cooker.

[Object of the Invention] The present invention has been made in view of the circumstances in Article 4, and its purpose is to detect the boiling state of water in steel extremely accurately regardless of the amount of rice cooked. Can-C1
It is an object of the present invention to provide a boiling detection device for a rice cooker that can accurately control rice cooking based on the detection result.

[Summary of the Invention] In order to achieve the above object, the present invention determines that a time-series temperature gradient of steel humidity is below a predetermined target temperature gradient and outputs a boiling detection signal. The boiling detection means is further provided with a rice cooking amount detection means that outputs a rice cooking amount signal corresponding to the rice cooking amount, and the boiling detection means is configured to detect the rice cooking time indicated by the rice cooking amount signal indicated by -. The structure is such that the target temperature gradient is changed to become smaller as the temperature increases.

[Embodiments of the Invention] Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1 to FIG. 6.

In Fig. 2, 1 is the rice cooker body consisting of an inner frame 2 and an outer frame 3, etc., 4 is a lid, 5 is a steel removably housed inside the inner frame 2, and 6 is a J that heats this 'm5. , for example, a rated output 60 installed in the space between the bottoms of the inner frame 2 and outer frame 3.
This is a heater for rice cooking. Reference numeral 7 denotes a heat-sensitive cap that is arranged so as to be able to move up and down so as to penetrate through the bottom of the inner frame 2. This cap is always biased in the opposite direction by the spring force of a compression coil spring 8, and the steel 5 is attached to the inner frame 2. It is arranged so as to be in pressure contact with the outer bottom of the steel 5 while housed in the steel 5. Reference numeral 9 denotes a thermistor, for example, a thermistor as a heat-sensitive element provided in the heat-sensitive cap 7 to detect the temperature of the steel 5.
0 is a steel switch for preventing dry cooking that is turned on by being pressed by a heat-sensitive cap 7 only when the pot 5 containing rice and water is housed in the inner frame 2. Further, 11 is an operation panel installed on the side of the rice cooker main body 1, and 12 is a case provided on the outer bottom of the rice cooker main body 1. Inside this case 12, the temperature detected by the thermistor 9 and the operation 6 A control circuit 13 for controlling power on/off of the heater 6 based on human power from the panel 11 is housed.

FIG. 1 shows the configuration of the l-open control circuit 13 and the parts related thereto that are directly related to the gist of the present invention, and will be described below.

In addition, in FIG. 1, the control circuit 13 combines each functional part.1. Although the hardware is shown in ``m'' and ``J'', the present invention is not limited to this, and it goes without saying that ``C'' may also be used, in which each of the above-mentioned functional parts can be directly changed by the microphone program.

In FIG. 1, -C114 is a switching element.

For example, a triac is connected between both terminals of an AC power source 15 via the heater 6 and the chain switch 10 in series. 16 is a light-emitting diode A-domain 16a and a phototransistor 16b, J: a coupler consisting of;
A half-wave voltage of an AC power supply 15 is applied to the light emitting diode 16a via a diode 17 and a resistor 18.

19 is a DC constant voltage circuit that receives the output of the AC power supply 15;
Power is supplied to each circuit section described below from the output lines La and IJ.

Reference numeral 20 denotes an initialization circuit consisting of, for example, a differential circuit, which generates an initialization pulse P every time the power is turned on. Output. 21 is a waveform shaping circuit that shapes the output of the photocoupler 16 (voltage output corresponding to the half-wave output of the AC power supply 15) into a rectangular wave; 22
23 is a first frequency dividing circuit that divides the output of the waveform shaping circuit 21 to generate a time signal, for example, a clock pulse P1 with a period of 1 second. This is a second frequency dividing circuit that outputs a clock pulse P2 having a cycle of, for example, 10 seconds. Reference numeral 24 denotes an A-D converter which together with the thermistor 9 constitutes the temperature detection means 25, which outputs a digital value of the temperature detection signal Sd corresponding to the temperature of the steel 5 detected by the thermistor 9. Reference numerals 26 and 27 indicate first and second temperature value storage units that store numerical values corresponding to temperatures used to detect rice cooking m, for example, 70°C and 80°C, respectively; 28 indicates a predetermined lower limit temperature, such as 90°C;
a third temperature value storage unit storing numerical values corresponding to 2;
9 is a fourth memory which stores a numerical value corresponding to, for example, 110°C.
This is the wet town value storage section of . Further, 30 to 39 are fifth to fourteenth temperature value storage sections, in which, for example, the following numerical values are stored, as shown in FIG. That is, the fifth temperature value storage unit 30 stores a numerical value corresponding to 2°C, and the sixth temperature value storage unit 30 stores a value corresponding to 2°C. Eighth and eleventh temperature value storage unit 3
1.33 and 36 respectively store numerical values corresponding to 3°C, seventh and tenth temperature value storage units 32 and 35 respectively store numerical values corresponding to 1°C, and the ninth and twelfth temperature value storage units 32 and 35 store numerical values corresponding to 1°C, respectively. The temperature value storage units 34 and 37 each store a value corresponding to 5°C, the thirteenth temperature value storage unit 38 stores a value corresponding to 112°C as the heater power-off temperature DZ, and the fourteenth temperature value storage unit 38 stores a value corresponding to 112°C as the heater power-off temperature DZ. The temperature value storage unit 39 stores the temperature D for starting double cooking.
A numerical value corresponding to 103° C. is stored as r.

40 and 41 are standards for detecting the amount of cooked rice, for example, 2.
The first and second parts memorize numerical values corresponding to minutes and quarters.
This is a time value storage unit. 42 to 51 are 3rd to 12th
As shown in FIG. 1, the following numerical values are stored in the time value storage section. That is, the third time value storage section 42 stores a numerical value corresponding to 7 minutes, the fourth time value storage section 43 stores a numerical value corresponding to 9 minutes, and the fifth and eighth time value Storage units 44 and 4
7 stores a numerical value corresponding to 0 seconds, the sixth and ninth time value storage sections 45 and 48 store a numerical value corresponding to 10 seconds, respectively, and the seventh and tenth time value storage sections 45 and 48 store a numerical value corresponding to 10 seconds, respectively. 46
and 49 respectively store numerical values corresponding to 20 seconds, the eleventh time value storage section 50 stores numerical values corresponding to 30 seconds as the double cooking heating reference time N, and the twelfth time value storage section 50 stores numerical values corresponding to 30 seconds as the double cooking heating reference time N. A numerical value corresponding to 15 minutes as the uneven driving time M is stored in the section 51.

52 to 64 are comparison circuits, which output a high level signal from the output terminal C when the input values to the input terminals A and B are in the relationship A2B, and output a low level signal from the output terminal C when the relationship A<B. Outputs level signal. Further, 65 is a comparison circuit equipped with an enable terminal En, which performs the same operation as the above-mentioned comparison circuits 52 to 64 only when the enable terminal En receives a high level signal, and the enable terminal [n has a low level signal]. While receiving a signal, a low level signal is always output from output terminal C. 66 and 67 are subtraction circuits, which subtract the input value for input terminal F from the input value for input terminal I, and output the subtraction result from output terminal [. Addition circuits 68 to 71 add the input value to the input terminal X, the input value to the input terminal Y, etc., and output the addition result from the output terminal 7. 72 to 75 are counters that count the number of input pulses to the clock terminal CK and output the count value from the output terminal Q, and when the pulse signal is received at the reset terminal R, the count contents are changed. It is now initialized. 76 to 79 are trigger circuits 1 to 79, which output a trigger pulse P3 for a short time when the input signal thereof rises. 80 is a delay circuit, which delays the input signal for a short time and outputs the delayed signal. 81 is a shift register having 24 unit registers, for example.
This means that every time a pulse signal is received at the clock terminal φ, the input/input that changes to the data terminal is sent to the first unit register 8.
In addition to reading data into 1a and storing it with lυ, the structure is such that the old stored data is sequentially shifted to the upper unit register each time new data is read, and when a pulse signal is received at the reset terminal R, the The memory data is initialized. In such a shift register 81, the twelfth unit register 81b, the first
The eighth unit register 81C2 is configured to output each stored data of the 24th unit register 81d. Reference numeral 82 denotes a memory circuit, which is initialized when a pulse signal is received at its reset terminal R, and is configured to memorize the value input for the first time to the input terminal from this initialized state. being done. Reference numeral 83 designates a heater drive circuit which outputs a gate signal SO and supplies it to terminals 1 to 1 of the triac 14 only when receiving a high level signal, and 84 designates a heater output control circuit which is driven only when receiving a high level signal. , this heater output control circuit 84 is
During driving, a pulsed control signal Sc with a duty ratio of 50%, for example, is output. Reference numerals 85 to 100 designate transfer gates, which are rendered conductive only when receiving a high level signal at their gate terminals.

Reference numerals 101 and 102 are a start switch for starting rice cooking and a stop switch for stopping rice cooking, which are provided on the operation panel 11, respectively.These are configured as momentary type push button switches, and are activated only when turned on. Pulse signals (high level signals Q) P4 and P5 are output to the corresponding lines, respectively. Also, 103 to 105 are R-S
Flip 70 knob, 106 to 115 are AND circuits, 1
16 to 118 are OR circuits, and 119 to 125 are inverters. In addition, 1st. The crying means 126 is constituted by the second frequency dividing circuit 22゜23 and the AND circuit 108,
1st. The second temperature value storage unit 26°27, the first . Second time value storage units 40, 41 . Comparison circuit 52, 53, 56, 5
7. The counter 72° AND circuit 106, 109 and the inverter 119° 120 constitute the rice cooking amount detection means 127, and the fifth temperature value storage section 30. Comparison circuit 65. Subtraction circuit 66, shift register 81 and transfer game
1-85, 86, and 87 constitute a boiling detection means 128, and a fourth temperature value storage section 29. 3rd degree fourth time value storage unit 42.43. Comparison circuit 58°59, counter 73
．． AND circuit 107, 110 and inverter 121, 1
22, a correction means 129 is constructed, including a fourteenth temperature value storage section 39 and fifth to twelfth time value storage sections 44 to 51. Comparison circuits 62, 63, 64. Addition circuit 70.71
゜Counter 74, 75. Trigger circuits 78, 79. Transfer gates 95 to 100. AND circuits 114, .
115 and the inverter 125 constitute a double cooking control means 130, and a sixth temperature value storage section 31. Comparison circuit 60. The subtraction circuit 67, the memory circuit 82, and the transfer gate 88 constitute boiling detection compensation means 131.

Next, the operation of the above structure will be explained with reference also to FIGS. 3 and 4. Incidentally, FIGS. 3A and 3B show the temperature detected by the reamister 9 (that is, the temperature of the steel 5) and the time change characteristics of the output of the heater 6, respectively, and FIG.゜53.5=1-. 55, 60, 61
,62,63,64.65. Heater output control circuit 84.
Switch to star 1 101. R-S flip-flop 1
03°104.105 each set output terminal Q, AND circuit 106, 107, 113, 115. Each output waveform from the OR circuit 118 is shown in association with its respective sign.

That is, when the steel 5 containing rice and a required amount of water is stored in the inner frame 2, the steel switch 10 is turned on in response to the storage. When the power is turned on in this state, the DC power supply circuit 19
While the photocoupler 16 is driven, the initialization circuit 2
Initialization pulse P from 0. is output, this initialization pulse PO causes the R-S flip-flop 103 to
is reset and a high-level signal is output from its reset output terminal O. This high-level signal initializes the counters 72, 74 and the memory circuit 82, and also resets the I'(-S flip-flop 105. Also, at this time, the R-S flip-flop 1
Since the trigger pulse P3 is output from the trigger circuit 76 which receives the high level signal from 03 via the OR circuit 117, the shift register 81 is initialized by the trigger pulse P3, and the same <OR circuit 117 is The R-S flip-flop 104 is reset by the high level signal outputted through the R-S flip-flop 104. After this, time to
<Refer to Figures 3 and 4), press the start switch 101.
When turned on, the R-S flip 70 knob 103 is set by the pulse signal P outputted in response to the turning on, and the high level signal from the set output terminal Q is set to A.
The signal is applied to ND circuits 112 and 113. At this time, one AND circuit 112 is given a low level signal from the set output terminal Q of the R-S flip-flop 104 which is in the reset state as described above, so its output remains a low level signal. However, the other AND circuit 113 receives a low level signal from the let output terminal Q of the R-S flip-flop 104 and outputs it to the inverter 124.
: R-S flip-flop 1 which is inverted to the high level signal and is also in the reset state.
Since the high level signal from the reset output terminal 0 of 05 is applied, a high level signal is output from the AND circuit 113 and is applied to the heater drive circuit 83 as a result. Therefore, a signal S is output from the heater drive circuit 83 to the gate 1 to turn on the triac 1/I, and in response, the AC power supply 15 outputs the signal S to the gate 1. Electricity is applied to the heater 6 via the triac 14 to heat the steel 5, and the rice cooking process is then started. As the rice cooking process progresses, the temperature 15 rises as shown in FIG. 3, and the temperature detection circuit 25 outputs a temperature detection signal 3d corresponding to the temperature gI5. Then, the temperature of the steel 5 is 70° C. stored in the first temperature value storage section 26.
At time t, the rice cooking amount detection unit 127 operates first. That is, in the rice cooking amount detection unit 127, the comparison circuit 52 determines that the temperature detection signal Sd input to the terminal A is the temperature corresponding to 170° C.J input to the terminal B from the first temperature value storage unit 26. A low level signal is output until time t1 when the value becomes equal to the value 1. After that, a high level signal is output. Further, the comparator circuit 53 operates until time t2 when the temperature detection signal Sd input to the terminal B becomes larger than the temperature value corresponding to 180° C. input from the second temperature value storage unit 27 for the terminal A. A high level signal is output, and after that time t2, a low level signal is output. Therefore, both comparison circuits 5 only during the period from time t1 to time t2.
A high level signal is output from 2゜53 and AND circuit 1
During this period, the pulse signal P1 with a period of 1 second from the first frequency dividing circuit 22 is applied to the AND circuit 10.
6 and is applied to the clock terminal CK of the counter 72. Therefore, as a result, the count value of the counter 72 becomes a value corresponding to the time Ta (time from time t1 to t2) required for the temperature of the steel 5 to rise from 70°C to 80°C.

Therefore, the time a measured as described above has the property of increasing or decreasing in proportion to the amount of rice cooked. That is, the count value of the counter 72 is compared to the comparator circuit 56.57.
The numerical values stored in 0.41 (corresponding to 2 minutes and 11 minutes) are compared.

At this point, the comparison circuit 56 compares the numbers 1 to 1 of the counter 72.
When the value is smaller than the 2 minute equivalent value (in other words, when there is relatively little rice cooking), a low level signal is output, and this low 1 novel signal is inverted by the inverter 119 to a high 1 novel signal which is the rice cooking amount signal. and is applied to line L1. In addition, the comparison circuit 57 outputs a high level signal as a rice cooking amount signal when the value of the counter 72 is equal to or greater than the value equivalent to 4 minutes (in other words, when the amount of rice cooked is relatively large), and outputs a high level signal as a rice cooking amount signal to line 1-3. give to Furthermore, when the count value of the counter 72 is equal to or greater than the value equivalent to 2 minutes but smaller than the value equivalent to 4 minutes (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparator circuit 56 to indicate that AND circuit 109
A low level signal is output from the comparator circuit 57, which is inverted to a high level signal by the inverter 120, and is then applied to the other input terminal of the -UAND circuit 109. As a result, That A
A high level signal serving as a rice cooking amount signal is outputted from the ND circuit 109 and applied to line L2. In short, the rice cooking amount detection unit 127 determines the amount of rice to be cooked based on the time required for the wet state of the steel 5 to rise from 70°C to 80°C.
The rice cooking amount signal (high level signal) indicating the determined unity is sent to line +1. It selectively outputs to L2, 1-3. When the amount of cooked rice detected in this way is relatively small, the transfer gates 85, 89.95 whose gate terminals are connected to the line L1 are in a conductive state, and when the amount of cooked rice detected is medium, , the gate terminal is line 1-2
The transfer gates 86, 90.96 connected to the line 1-43 speed up the conduction state, and when the detected amount of cooked rice is relatively large, the transformer 7 whose gate terminal is connected to the line 1-43
Seven gates t-87, 91, and 97 become conductive. At this time, the 7.
8th. The temperature value stored in the ninth temperature value storage unit 32, 33, 34 is used to adjust the heater power-off temperature Dz (the temperature value stored in the thirteenth temperature value storage unit 38, that is, 112°C). Each of these stored temperature values is selectively given to the input terminal Y of the adder circuit 68 depending on the magnitude of the detected rice cooking amount, and the adder circuit 68 receives the temperature input in this way. The value is added to the numerical value (heater power-off temperature DZ) stored in the thirteenth temperature value storage section 38 and output. Also, the fifth gate corresponding to the transfer 1 gate 95, 96, 97 which is selectively turned on as described above. 6th
゜The time value stored in the seventh time value storage unit 44, 45, 46 adjusts the double cooking heating reference time N (the time value stored in the eleventh time value storage unit 50, that is, 30 seconds). The values between each memory 1 are added to the adder circuit 70.
is selectively given to the input young child Y according to the magnitude of the detected rice cooking amount, and in the adding circuit 70, the time value thus inputted is stored in the eleventh time value storage section 50. It is added to the numerical value (double cooking heating reference time N) and output.

After this, when the temperature of the steel 5 further increases and reaches the lower limit temperature of 190° C. stored in the third humidity value storage section 28 (
At time t3), each input value to the input terminals A and B of the comparator circuit 54 has a relationship of A≧B, and the output of the comparator circuit 54 is inverted to a high level signal. As a result,
The AND circuit 108 which receives the above-mentioned high level signal at one input terminal allows the input to the other input terminal, that is, the passage of the pulse signal P2 with a period of 10 seconds from the second frequency dividing circuit 23 in the timekeeping means 126. At the same time, the comparison circuit 65 which also receives a high level signal from the comparison circuit 54 via the delay circuit 80 to the enable terminal En becomes operational, and accordingly, the boiling detection function of the boiling detection means 128 becomes effective. It comes to be That is, when the pulse signal P2 begins to pass through the AND circuit 108, the pulse signal P2 passes through the clock terminal φ of the shift register 81.
The shift register 81
is the input to the data terminal, that is, the temperature detection signal Sd
is read and stored every 10 seconds, and each time a new temperature detection signal Sd is read, the old temperature detection signal Sd is sequentially shifted to the intermediate register of negative digits. In this case, the current temperature detection signal SdJ and the temperature detection signal Sd from 120 seconds (2 minutes) ago are stored in the 12th unit register 811).
180 seconds (3 minutes) from the current temperature detection signal Sd.
The previous temperature detection signal Sd is stored, and the 24th intermediate register 81d stores the 24th temperature detection signal Sd from the current temperature detection signal Sd.
The temperature detection signal Sd from 0 seconds (4 minutes) ago is now stored. At this point, the data stored in the unit registers 81b, 81c, and 81d are applied to the input terminal E of the subtraction circuit 66 via the corresponding transfer games 1 to 85, 86, and 87, respectively. As mentioned above, when the amount of rice to be cooked is relatively small, the 1 to 1 ratio gate 85 is turned on quickly, and the data stored in the unit register 81b is applied to the input terminal of the subtraction circuit 66.
Similarly, when the amount of cooked rice is medium or relatively large, the data stored in the unit registers 81c and 81d are directed to the input terminal F of the subtraction circuit 66. The temperature detection signal Sd is directly input to the other input terminal of the subtraction circuit 66, so that the subtraction circuit 66 calculates the current temperature detection signal from the value indicated by Sd. The value indicated by the temperature detection signal Sd 2 minutes ago, 3 minutes ago, or 4 minutes ago, which corresponds to the Wtlu time in the embodiment of the present invention, is subtracted, and the result of the subtraction is The temperature rise value of the chain 5 within 2 minutes, 3 minutes, or 4 minutes becomes a value corresponding to the time-series humidity gradient of w45. Therefore, the temperature of the steel 5, that is, the temperature detection signal Sd
The rate of increase in the temperature of the pot 5 has a property of becoming approximately zero once the water in the copper 5 reaches a boiling state. If it is detected that the temperature has dropped below this value, it can be determined whether or not the inside of the pot 5 has reached a boiling state. In order to accurately detect boiling, it is desirable to change the above-mentioned reference time according to the amount of cooked rice. In this embodiment, in order to accurately detect temperature, the reference time (
That is, the sampling time of the temperature detection signal Sd is automatically changed to 2 minutes, 3 minutes, or 4 minutes as described above. Then, in the comparison circuit 65, the output from the subtraction circuit 66 (the temperature increase value of the steel 5 within the three-step reference time determined according to the amount of rice cooked) and the fifth temperature value storage section 30 is compared with the numerical value (equivalent to 2°C) stored as the comparison temperature value in A rising detection signal @Sl consisting of a high level signal J: is output from 65 (time j4).

Therefore, at the time t4, the storage contents of the storage circuit 82 are in an initialized state, and a numerical value (corresponding to 3° C.) is stored in the sixth temperature value storage section 31 from the stored value.
The output of the subtraction circuit 67 that subtracts is a negative value, and the comparison circuit 60 is in a state of outputting a low level signal. Therefore, both input terminals of the OR circuit 117 are connected to the comparison circuit 6.
A low level signal is applied from the reset output terminal 0 of the 0 and R-3 flip-flop 103, and this low level signal is inverted to a high level signal by the inverter 123 and applied to one input terminal of the AND circuit 111. . Therefore, when the boiling detection signal Sz (high level signal) is output as described above at time t4, AND
A high level signal is output from the circuit 111 and the R-S flip-flop 104 is set. Then, the output of the AND circuit 113, which had been outputting a high level signal, is inverted to a low level signal, and the AND circuit 112 outputs a high level signal.
R-S flip 70 tabs 103 and 104 for each input terminal of
Each set of output terminals Q and R-S flip 70 tabs 10
5 is given a high level signal from the reset output terminal Q, the AND circuit 112 outputs a high level signal, and in response, the heater output control circuit 8
4, a pulse-like control signal SC with a duty ratio of 50% is output and applied to the heater drive circuit 83.

As a result, the triac 14 is turned on and off at a decoty ratio of 50%, and the rated output of the heater 6 is 600 watts, so the heater 6 has an output of 300 watts, which is half of the rated output. The output starts to generate heat. Also, at the above time 1:4, the R-S flip-flop 104 is set to l? When the trigger circuit 77 is driven and the trigger pulse P3 is output from now on, the counter 73 is initialized by the trigger pulse P'3, and the 1-transfer gate 88 becomes conductive. The temperature detection signal Sd at time t4 (corresponding to the temperature of the plane 5 at the time of detection of the boiling state) is stored in the storage circuit 82. Also, at this point, there is still enough water left in the pot 5 and its temperature does not exceed 100'C, so the temperature detection signal 3d and the fourth temperature value corresponding to the temperature of the steel 5 are The comparator circuit 55 that compares the value stored in the storage unit 29 (corresponding to 110°C) outputs a high level signal. AND that receives a high level signal
The circuit 107 receives the pulse signal P1 from the first frequency dividing circuit 22.
(1 second cycle) is allowed to pass. Therefore, the count value of the counter 73 initialized as described above no longer indicates the elapsed time from time t4. When the rice cooking process further progresses and the inside of the steel 5 exhibits a so-called dry-up state, the temperature of the steel 5 will rise dramatically. When the temperature reaches 110°C at t, the input terminals A and B of the comparator circuit 55 have a relationship of Δ<B, and the output is inverted to a low level signal, so that the AND circuit 107
blocks the passage of the pulse signal P1, and the counting operation of the counter 73 is stopped. Therefore, as a result, the count value of the counter 73 corresponds to the required time Tb (corresponding to the duration of the boiling state) from time t4 when the boiling detection signal SZ is output to time t5 when the temperature of the pot 5 reaches 110°C. It becomes equivalent.

Like the time Ta from time t1 to t2 described above, the time Tb measured as above has the property of increasing or decreasing in proportion to the amount of rice cooked, and is also influenced by the ratio of rice to water during cooking. The correction means 129 has the above-mentioned time Tll
Based on the count value of the counter 73 corresponding to , the rice cooking amount detected by the rice cooking amount detection means 127 is corrected as follows.

That is, the count value of the counter 73 is the value of the comparison circuit 58, 59.
By 3rd. The respective numerical values (corresponding to 7 minutes and 9 minutes) stored in the fourth time value storage sections 42 and 43 are compared. At this time, the comparator circuit 58 outputs a low level signal when the count value of the counter 73 is smaller than the value equivalent to 7 minutes (1!!!!!! In other words, when the amount of cooked rice is relatively small), the comparator circuit 58 outputs a low level signal. is inverted to a high level signal by the inverter 121 and applied to the line L4. Further, the comparison circuit 59 outputs a high level signal and supplies it to the line L6 when the count value of the counter 73 is equal to or greater than the value equivalent to 9 minutes (in other words, when the amount of cooked rice is relatively large). When the count value of the counter 73 is equal to or greater than the value equivalent to 7 minutes and smaller than the value equivalent to 9 minutes (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparison circuit 58, and this is ANDed. A low level signal is applied to one input terminal of the circuit 110 and is outputted from the comparator circuit 59, which is inverted to a high level signal by the inverter 122, and the AN
The signal J applied to the other input terminal of the D circuit 110 is turned on, and as a result, a high level signal is output from the AND circuit 110 and applied to the line L5. When the amount of cooked rice detected in this way is relatively small, the transfer gate 92 whose gate terminal is connected to the line L4
．． 98 quickly becomes conductive, and when the detected amount of cooked rice is medium, transfer gates 1-93 and 99 whose gate terminals are connected to line L5 exhibit a conductive state, and furthermore, the detected amount of cooked rice is relatively large. In this case, the transfer gate 94.100 whose gate terminal is connected to the line L6 becomes conductive. At this time, the 10th. 11゜-3〇- The furniture values stored in the 12th temperature value storage section 35, 36. 112° C.), and each of these stored temperature values is selectively given to the input terminal Y of the adder circuit 69 depending on the length of the time Tb. The rice cooking amount detection circuit 127 adds the input temperature value to the numerical value signal @ (i.e., temperature value 1 for heater power cutoff) 7 from the addition circuit 68.
The temperature value corresponding to the amount of cooked rice detected by the rice cooker 127 is further added to the temperature value corresponding to the amount of rice cooked. In addition, the 8th one corresponding to 1 Heransfagame)-98, 99, 100, which is also selectively conductive. 9th. The time value stored in the tenth time value storage unit 47, 4.8.49 is also the double cooking heating reference time N (the time value stored in the eleventh time value storage unit 50, that is, 30 seconds). These memory time values are selectively given to the input terminal Y of the adder circuit 71 according to the length of the time T+1, and the adder circuit 71 The input time value is added to the numerical signal from the adding circuit 70 (i.e., the rice cooking amount detection circuit 1 for the double cooking heating reference time N)
27, the time value corresponding to the detected amount of cooked rice (added) is further added to the amount of time added, thereby correcting the added time value by the amount of cooked rice detection section 127, and thus the detected amount of cooked rice. It acts on

Now, at the subsequent time t6, the rice cooking amount detection unit 127 determines that the temperature of the steel 5 is the cooked rice temperature corresponding to the output from the adder circuit 69 (i.e., the heater power-off temperature Dz (112°C)). When the temperature value corresponding to the detected rice cooking amount and the corrected temperature value by the correction means 129 reach the [added temperature], each input value to the input terminals A and B of the comparator circuit 61 becomes in the relationship A2B, The comparison circuit 61
Since a high level signal is output from the RS flip-flop 105, the R-S flip-flop 105 is set. Then, a low level signal from the reset output terminal Q of the R-S flip-flop 105 is applied to the AND circuit 112, and the output of the AND circuit 112 is inverted to a low level signal, so that the heater output control circuit 84 is stopped. In response, the heater drive circuit 83 stops outputting the gate signal SO and keeps the triac 14 in the turned-off state, that is, the heater 6 is cut off, thereby ending the rice cooking process.

At this time, the high level signal from the set output terminal Q of the R-S flip-flop 105 is applied to the AND circuit 1.
14 and 115, the AND circuit 114 allows the pulse signal P1 to pass, and the double cooking control means 130 functions accordingly to shift to the uneven process. . According to the above mold, the temperature of Kabura 5 is
Humidity value (7th
, No. 8. Any one of the temperature values stored in the ninth temperature value storage section 32, 33, 34) and the corrected temperature value stored in the correction means 129 (the 10th, 11th, 12th temperature value storage section 3)
When the finished cooking temperature reaches 33, which is obtained by adding any one of the temperature values stored in 5, 36, and 37, the rice cooking process is completed and the rice cooking process is shifted to the uneven process. describes the effect in this uneven process. In the case of this embodiment, the above-mentioned cooking temperature is stored in the seventh to thirteenth temperature value storage units 32 to 3.
The temperature varies between 114° C. and 122° C. depending on the stored contents of No. 8.

The counter 75 in the double cooking control means 130 has been clocking the pulse signal P1 since the power was turned on, and therefore, at time t6, the count value is at least equal to the numerical signal (main) output from the adding circuit 71. In the case of the embodiment, the maximum value corresponds to 100 seconds), and as a result, each input value to the input terminals A and B of the comparator circuit 64 has a relationship of A<B, and the comparator circuit 64 receives a low level signal. is outputting. Further, since the other counter 74 in the double cooking control means 130 starts counting operation from time t6, at this point, each numerical value input to the input terminals A and B of the comparator circuit 62 is equal to that of A2B. In this connection, a high level signal is output from the comparison circuit 62. Then, when the heater 6 is cut off at time 6, the temperature of the steel 5 gradually decreases after overheating as shown in FIG. When the temperature drops to the double cooking start temperature iDr (103°C) stored in the fourteenth temperature value storage section 39,
The input values for the input terminals A and B of the comparator circuit 63 are A
Since the relationship is 2B and a high level signal is output,
The high level signal was received by the trigger circuit 78.
The trigger pulse P3 is started to be output, and the counter 75 is initialized from the first to the trigger pulse P3. In other words, each input value of the input terminals A and B of the comparator circuit 64 is A2B.
As a result, a high level signal is output from the comparison circuit 64, and in response, a high level signal is applied to all -C input terminals of the AND circuit 115, and the output of the AND circuit 115 becomes high level. The signal becomes inverted. As a result, the heater drive circuit 83 receiving the high level signal from the AND circuit 115 turns on the triac 14 and re-energizes the C heater 6, and in response, double heating is performed 4f. At this time, the counter 75 indicates the elapsed time from time t7 when the temperature of the steel 5 decreased to 103°C.
At time t8, the count value corresponds to the output of the adder circuit 71 (i.e.: reference time for cooking melon heating N(
30 seconds), the comparison circuit 6/1
Since each input value to the input terminals A and B becomes in the relationship A<B, and the output of the comparison circuit 64 is inverted to the []- level signal, the output of the AND circuit 115 is also inverted to drive the heater. The circuit 83 turns off the triac 14, thereby cutting off the power to the heater 6 and stopping the double heating. After this, at each time tq and t11 when the temperature of the pot 5 reaches -B and then decreases to 103°C due to double cooking heating, the heater 6 is energized again to perform double cooking heating in the same manner as described above. At the same time, such double-cooking heating is performed at each time T1o at which the count value of the counter 75 corresponds to the output from the adder circuit 71.
, j12. Then, after time 1:6, the first
The uneven driving time M(
At time t13, when 15 minutes) have elapsed, the counter 77
Since the count value of 1 exceeds the value corresponding to the uneven operation time M and the output of the comparator circuit 62 is inverted to a low level signal, the state in which the AND circuit 115 outputs a low level signal, and thus the heater drive circuit 83 is kept in a stopped state, and the uneven stroke is completed. Then, when the output of the comparison circuit 62 is inverted to a low level signal as described above, the output of the inverter 125 is inverted to a high level signal and the trigger pulse P3 is output from the trigger circuit 79. The R-8 flip-flop 103 is reset by P3, and from then on, the process proceeds to a warming process using a warming heater (not shown).

To summarize, in the uneven process, when the temperature of WA5 drops to 103°C, which is the temperature for starting double cooking [ The time value (5th, 6th, 7th time value storage unit 4.4, 4.
5. /16) and the corrected time value by the correction means 129 (any one of the time values stored in the 8th, 9th, and 10th time value storage units 47, 48, 49) 1), the heater 6 is cut off and the double cooking heating is terminated. The time is changed between 30 seconds and 70 seconds depending on the contents stored in the fifth to eleventh time value storage units 44 to 50.

So far, we have described the effect when the temperature of uA5 continues to rise without decreasing after the boiling detection signal Sz is output at time t4 and the output of the heater 6 is reduced to half of the rated value. However, in the following, after reducing the output of heater 6 in this way,
5 and 6 will be explained with reference to FIGS. 5 and 6, which are similar to FIGS. 3 and 4, respectively. In other words, the phenomenon in which the temperature of the steel 5 decreases when the output of the heater 6 is reduced by half means that the water in the steel 5 has not yet boiled? 7I! rising detection signal Sz
Such a phenomenon can occur, for example, when seasonings such as soy sauce put into the steel 5 burns at the bottom of the chain 5 when making boiled rice. This is thought to be due to the increase in the gap between the temperature of the water in the steel 5 and the temperature detected by the thermistor 9. Therefore, time 14 in FIGS. 5 and 6
When the output of the heater 6 is halved at , the temperature of the steel 5 at that time (i.e., the boiling detector g!1
A temperature detection signal Sd corresponding to the temperature of the sheath 5 detected to indicate that the boiling point 28 is in the boiling state is stored in the storage circuit 82 in the boiling detection compensating means 131. At this point, the subtraction circuit 67 in the boiling detection compensation means 131 converts the stored numerical value (
3° C.), and the temperature value Tp corresponding to the subtraction result is input to the input terminal Δ of the comparator circuit 60. Therefore, after the temperature of the steel 5 has decreased by one node to the above-mentioned temperature value Tp (time t41), the output of the comparison circuit 60 is inverted to a high level signal, and in response to this, the R- When the S flip-flop 104 is reset to 1-,
The trigger circuit 76 is driven, and the shift register 81 is initialized by trigger pulses P1 to P3 from the trigger circuit 76. Therefore, the output of the AND circuit 112 is inverted to a low level signal, and the output of the AND circuit 113 is inverted to a high level signal, so that a high level signal is continuously given to the heater drive circuit 83. Accordingly, the heater 6 generates heat at the rated output, that is, 600 watts. In addition, in response to the above-mentioned J: sea urchin shift 1 to register 81 being initialized, the boiling detection means 127 starts to perform the same boiling state detection operation as described above, and for example, at time taz, the comparison circuit 65 detects the boiling state. When the detection signal 3z is output, the output j of the heater 6 is halved again. Further, after this, the same operation as described above is repeated on the platform where the temperature of vA5 has decreased again, and as described above, the boiling detection compensating means 131 makes the detection operation of the boiling detecting means 128 more accurate. Naru J: It functions like a sea urchin.

According to the present embodiment described above, the following effects can be achieved. That is, instead of detecting the boiling state of the water in the pot 5 based on a predetermined absolute upper limit temperature as in the conventional method, the boiling state of the water in the M5 is detected as soon as the water in the pot 5 reaches a boiling state. The temperature gradient has become below a certain gradient (specifically, the amount of change in the humidity of the pot 5 within a predetermined reference time has become a certain comparison temperature 11ffl' stored in the fifth temperature value storage section 30). J (2°C) or below), the contact state between the heat-sensitive cap 7 and the bottom of the pot 5, the thermistor 9 or A-D constituting the temperature detection means 25 Even if there are variations in the circuit constants of the converter 24 and changes in its characteristics over time, changes in atmospheric pressure, or fluctuations in the boiling point due to seasonings being thrown into the steel 5 when making cooked rice, etc. , the boiling state of the water in the pot 5 can be accurately detected. In addition, when detecting the boiling state in this way, the temperature gradient of the pot 5 changes depending on the size of the rice to be cooked, so the boiling state cannot be detected as described above when the amount of rice to be cooked is different. Although there is a risk of inaccuracy, in this embodiment, the temperature gradient of 6145, which is the target at the time of boiling detection, is changed depending on the amount of cooked rice detected by the rice cooking amount detection means 127 (specifically, the temperature gradient (The reference time required when measuring the amount of rice is changed), so the boiling state of the water in the pot 5 can always be accurately detected even when the amount of rice cooked is different. In this embodiment, after the heater 6 is made to generate heat at the rated output until the boiling state is detected,
This configuration performs rice cooking control by reducing the output of the heater 6 by half, but in this case, as mentioned above, since the boiling state is accurately detected, the rice cooking control described above can be performed strictly. It can fully satisfy the so-called "medium-sized" condition, which is one of the conditions for cooking rice deliciously, and it can also cook rice with less stickiness, and overall the rice is well-cooked. obtain. Of course, in this way, the boiling state in the steel 5 is accurately detected, and the output of the heater 6 is halved after the boiling is detected. can reliably prevent boiling over. Furthermore, in this embodiment, the larger the amount of cooked rice detected by the rice cooking amount detection means 127, the more unnecessary moisture remains in the steel 5 during dry-up. Since the temperature, that is, the temperature at which the rice is cooked, is raised, the rice can be cooked well from this aspect as well. Moreover, in this case, the correction means 129 is provided,
Since the rice cooking amount detected by the rice cooking amount detection means 127 is corrected according to the length of the period during which the water in the tAb is in a boiling state, the rice can be cooked according to the size of the rice cooking amount and the ratio of rice to water during cooking. Control can be performed more strictly. Also,
The three-claw cooking heating time during the unevenness process is also changed to a time corresponding to the amount of cooked rice detected by the rice cooking amount detection means 127 and corrected by the correction means 129, so that it is possible to prevent the rice from becoming alpha. You can do as much as you need and make the cooked rice even more delicious. In addition, when making cooked rice, the boiling detection compensation means 131 compensates for errors in boiling detection caused by seasonings such as soy sauce put into the steel 5 burning. Even if there is a discrepancy between the temperature detected by the humidity detection means 25 and the actual temperature inside the steel 5, such as when the inside of the steel 5 falls into a special state as described above, the boiling state of the water inside the steel 5 can be determined. can be detected very accurately.

Furthermore, in each of the above embodiments, the function of the boiling detection means 128 is activated only when the temperature of the steel 5 reaches the lower limit temperature (90° C.) stored in the third temperature value storage section 28. Therefore, there is no possibility that a period during which the temperature gradient is flat, such as at the time when the temperature of the steel 5 rises as indicated by G in FIG. 3, will be mistakenly detected as a boiling state.

A second embodiment of the present invention is shown in FIG. 7, and only the differences from the first embodiment will be described below. That is, the second embodiment is characterized in that, in place of the boiling detection means 128 in the first embodiment, a boiling detection means 132 having a different function is provided. 132 will be described. In the boiling detection means 132, 133 is a shift register having, for example, 12 unit registers, and the data stored in the 12th unit register 133a is applied to the input terminal E of the subtraction circuit 134.

The shift register 133. A subtraction circuit 134 and a comparison circuit 13 receiving the output of the cylinder reduction circuit 134 at an input terminal B.
5 is a shift register 81.5 in the first embodiment.
It has the same functions as the subtraction circuit 66 and the comparison circuit 65, respectively. Also, 136.137.138 is the 15th
．． 16th. In the seventeenth temperature value storage section, these are respectively stored as reference temperatures of 2°C, 1.5°C, and 1°C in the embodiment of the present invention.
A numerical value corresponding to °C is stored. Furthermore, 139.
140.1/1.1 is each of the above storage units 136, 137.1
With transfer gates provided corresponding to 38,
Each goo 1~terminal is line L1. Connected to L2 and L3.

In this embodiment, the current temperature detection signal Sd is applied to the input terminal of the subtraction circuit 134, and the data stored in the unit register 133a of the shift register 133, that is, the temperature detected at a time point 120 seconds (2 minutes) ago The signal Sd is given to the input terminal E of the subtraction circuit 134, and therefore the numerical signal given from the subtraction circuit 134 to the input terminal B of the comparison circuit 135 corresponds to the temperature rise value of the steel 5 over a fixed period of 2 minutes. It becomes what it is. At this time, any one of the transfer gates 139 to 141 is in a conductive state depending on the amount of cooked rice detected by the rice cooking amount detection means 127, and the 15th. Any one of the stored numerical values in the 16th and 17th temperature value storage sections 136, 137, and 138 is given to the input terminal A of the comparator circuit 135 as a reference temperature. Therefore, in the comparator circuit 135, input terminals A, B
When each input value of has a relationship of A2B, in other words, 2
When the temperature rise value of the steel 5 per minute becomes equal to or less than the reference temperature 46, a boiling detection signal 3z consisting of a high level signal is output.

In short, in this embodiment as well, when the temperature increase gradient of the steel 5 falls below a predetermined target temperature gradient (specifically, the amount of change in the temperature of the steel 5 within a certain period of time falls below a predetermined reference temperature). The boiling detection signal Sz is outputted when the amount of rice cooked is below 100%), and the reference temperature is automatically changed depending on the amount of rice cooked, thereby achieving the same effect as the above embodiment. I can do it.

In each of the above embodiments, the temperature of the steel 5 is 70°C to 80°C.
A rice cooking amount detecting means 127 configured to detect the amount of rice cooked based on the time required for the rice to rise to the temperature is provided.
．． The memory value of 27 is not limited to this, and steel 5
It is also possible to provide a rice cooking amount detection means having a similar structure, such as one that detects the amount of cooked rice by measuring the entire weight of the rice. Of course, the storage contents of each of the other temperature value storage units 28 to 39, 136 to 138 and each of the time value storage units 40 to 51 are not limited to the above embodiments, and in particular, the storage contents of the other temperature value storage units 28 to 39, 136 to 138 and each of the time value storage units 40 to 51 are The numerical values stored in the storage section 39 of 14 may be replaced by the numerical values stored in the storage circuit 82. Furthermore, in each of the embodiments described in Section 2, the measurement of the duration of the boiling state by the correction means 129 is performed using the numerical value (110
℃), but instead of this, steel 5
It is also possible to detect the point in time when the temperature of the boiling water rapidly rises, and measure the boiling duration based on the detection result. Furthermore, in each of the above embodiments, the rice cooking amount detected by the rice cooking amount detection means 127 is ranked into three levels.
These may be roughly ranked in multiple stages, and of course, in this case, the configurations of the boiling detection means 128 or 132 and the correction means 129 will be changed accordingly; By doing so, boiling detection can be performed more precisely. In each of the above embodiments, the electric power when heating the three-claw rice cooker is changed by time control, but other configurations may be used as long as the average power of the heater 6 is changed. The energization time in step 6 does not need to be constant each time as in each of the above embodiments, and may be set to become shorter in sequence during each three-claw heating process.In addition, the heater output control circuit 84 may be replaced with a configuration that reduces the output of the heater 6 using a phase control method, and other switching elements such as a relay may be used instead of the triac 14.Furthermore, In the above example,
Although the description has been given of a device that performs only the normal rice cooking operation, it goes without saying that other rice cooking functions such as porridge cooking and brown rice cooking may be added in addition to this.

In addition, the present invention is not limited to the embodiments described in "-" and shown in the drawings, but can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, the boiling state of water in the steel can always be detected extremely accurately regardless of the amount of rice being cooked. This provides an excellent effect of accurately controlling rice cooking based on the detection results.

[Brief explanation of drawings]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a block diagram of the electrical configuration, FIG. 2 is a partially cutaway side view of the rice cooker, and FIG. The figure is a characteristic diagram of changes in pan temperature and heater output, Figure 4 is a timing chart showing the output waveforms of each part in Figure 1, and Figure 5 is a change in pan temperature and heater output under conditions different from those in Figure 3. The characteristic diagram, FIG. 6, is a timing chart showing the output waveforms of each part in FIG. 1 in a state different from that in FIG. 4. Further, FIG. 7 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention. In the figure, 1 is the rice cooker body, 5 is a pot, 6 is a heater, 7 is a heat-sensitive cap, 9 is a thermistor, 10 is a pot switch, 13 is a control circuit, 25 is a temperature detection means, 83 is a heater drive circuit, and 84 is a Heater output control circuit, 101 start switch, 102 switch to switch 1, 126 64 o'clock means,
127 is a cooking rice amount detection means, 128.132 is a boiling detection means, 129 is a correction means, 130 is a three-claw cooking control means, 1
31 indicates boiling detection compensation means.

Claims (1)

[Scope of Claims] 1. Temperature detection means for outputting a temperature detection signal according to the temperature of the pot, time measurement means for outputting a time signal indicating the elapsed time during rice cooking operation, and a rice cooking amount signal according to the amount of rice cooked. a rice cooking amount detection means that outputs a rice cooking amount, and measures a time-series gradient of the pot temperature based on the temperature detection signal and the time signal, and controls the pot temperature when the measured temperature gradient becomes equal to or less than a predetermined target temperature gradient. boiling detection means for determining that the water in the rice cooker is in a boiling state and outputting a boiling detection signal; 1. A boiling detection device for a rice cooker, characterized in that the boiling detection device is configured to change the temperature so that 2. The boiling detection means is provided to measure the temperature gradient based on the amount of change in the temperature detection signal within a predetermined reference time, and the reference time becomes longer as the amount of cooked rice indicated by the rice cooking amount signal increases. The boiling detection device for a rice cooker according to claim 1, characterized in that the boiling detection device is configured to change the boiling state as follows. 3. The boiling detection means is provided to measure the temperature gradient by comparing the amount of change in the temperature indicated by the temperature detection signal within a certain period of time with a reference temperature, and the boiling detection means is configured to measure the temperature gradient by comparing the amount of change in the temperature indicated by the temperature detection signal within a certain period of time with a reference temperature, and the boiling detection means The boiling detection device for a rice cooker according to claim 1, characterized in that the boiling detection device for a rice cooker is configured to change the temperature so that the higher the amount, the lower the temperature. 4. The boiling detection means is configured to enable the boiling detection function only when the temperature indicated by the temperature detection signal exceeds a predetermined lower limit temperature. The boiling detection device in the rice cooker described in . 5. Claim 1, characterized in that the rice cooking amount detection means is configured to detect the rice cooking amount according to the magnitude of the amount of change in temperature per unit time indicated by the temperature detection signal. The boiling detection device in the rice cooker described in .