JPS63302223A - Heating appliance - Google Patents

Abstract

PURPOSE:To prevent the occurrence of overshoot and to provide excellent cooking performance, by providing a sensor to detect the in-chamber temperature of a heating chamber and a control circuit to control the in-chamber temperature by means of a level detected by the sensor. CONSTITUTION:An atmosphere thermister 17 to detect an in-chamber temperature is disposed to the side of a heating chamber 11, and when an in-chamber temperature is changed, the resistance of the thermister 17 is changed. The change is transmitted to a control circuit 10, and when temperature is increased to a value inputted from an oven key 5 and a set temperature key 6 of a control panel 4, a plane heater 15 is turned ON and OFF to control an in-chamber temperature to a set value. The control circuit 10 always reads the sensor level of an in-chamber temperature, detected by the atmosphere thermister 17, commencing with a time after starting of cooking. The control circuit stores a sensor level lo at a point of time when the level is lowered to a lowermost point to calculate ln=lo+Kn.(L-lo), wherein lo is a sensor level at a lowermost point after starting, L is the temperature regulating level of an atmosphere thermister, and Kn is a factor determined according to a food. After the sensor level reaches ln determined by the calculation formula, a heat source is kept OFF for seconds tn.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention utilizes the level detected by a sensor that controls the temperature inside the refrigerator, and allows a microcomputer to turn on and off the heat source.
By using FF, the temperature inside the refrigerator will not exceed a predetermined temperature, and the items to be heated will be heated at a predetermined temperature. This relates to a heating cooker whose purpose is to cook food to a desired state.

Conventional technology In recent years, with the spread of heating cookers such as open ranges, cakes and
Baking sweets such as kutsky choux in the oven is rapidly increasing at home. In addition, recent gourmet food trends have placed emphasis on improving the quality of food and speeding up the cooking time.

However, the cooking of these cakes, rinds, noodles, choux, etc. is sensitive to the heating temperature, and if the temperature exceeds a predetermined baking temperature, the temperature will drop below C or below, which is called overshoot. ), there was a tendency for the quality to become extremely poor. This is because if you overshoot, the food will be baked at a higher temperature than the optimal baking temperature for the food, so the surface of the food will be baked first and the moisture inside will not come out, making it taste raw. It is from.

In order to prevent this overshoot, conventionally, before placing the object to be heated in the heating chamber, it was common to perform raw firing until the temperature in the heating chamber reaches the baking temperature. ).

However, preheating takes time and wastes energy. Further, even if preheating is performed, there is a problem in that if it takes time to put the object to be heated into the heating chamber, the temperature inside the heating chamber will drop and overshoot will occur.

As a countermeasure to this problem, a method has been proposed to eliminate overshoot without preheating. In addition to the conventional first sensor that detects the temperature inside the refrigerator and controls the ON/OFF of the heater, this sensor is installed near the heater.
A second sensor is provided to detect the temperature of the heater itself,
This covers the delay in thermal response of conventional sensors and eliminates overshoot.

Problems that the invention aims to solve However, this configuration has the following problems.

First, since this second sensor must be installed near the heater, it must have excellent high temperature characteristics and is very expensive. Next, since the second sensor must be in complete contact with the heater, the mounting structure becomes complicated and workability is poor. In addition, it is easily affected by wind from outside and heat from lamps used to illuminate the interior of the refrigerator. Furthermore, although this second thermistor has excellent high-temperature characteristics, it is not suitable for controlling the temperature inside the refrigerator, and it has to use two thermistors in addition to the conventional thermistor, leading to technical problems such as increased costs. I'm holding it.

The present invention solves these conventional problems, and uses a sensor used in conventional heating cookers, and replaces the change in resistance due to temperature with a change in voltage. (hereinafter referred to as the sensor level) and the level corresponding to the set temperature, i.e., when the sensor level is below this level, the heat source is turned on, and when it is above this level, the heat source is turned off. This sensor level and control level are used to control various usage conditions, such as whether or not preheating is required, that is, various starting temperatures, and whether the door can be opened during cooking or if cooking is interrupted due to an operational error. The present invention also provides a heating cooker that eliminates overshoot and has excellent cooking performance.

Means for Solving the Problems The heating cooker of the present invention has a control section provided with a display device, means for setting the heating function, means for setting the heating temperature, means for setting the heating time, etc. on the front of the main body. , a heating chamber for storing an object to be heated in the main body, a heat source for heating the object to be heated in the heating chamber, a sensor for detecting the internal temperature of the heating chamber, and a temperature according to the level detected by the sensor. A control circuit for controlling the internal temperature of the refrigerator is provided, and after the start of cooking, the temperature control circuit changes from the temperature control level L of the sensor to the lowest level 7io detected by the sensor.
When the heat source reaches level l, which is determined by multiplying the value obtained by subtracting the value by a food-specific coefficient K determined by the food, the heat source is stopped for a certain period of time to eliminate overshoot of the internal temperature. It is something.

Function The heating cooker of the present invention utilizes the temperature control level L of the atmosphere thermistor and the lowest point level 7Io after starting, calculates ln=Ja+Kn (L j?o), and when that level is reached, the heat source is kept at a certain level. By performing the time pause F until the temperature control level L is reached, it has the effect of eliminating overshoot of the central temperature in the refrigerator and providing optimal quality of food.

EXAMPLE Hereinafter, a heating cooker according to an example of the present invention will be explained based on the drawings.

FIG. 1 is a perspective view of the main body of a heating device showing an embodiment of the present invention. A door 3 that can be opened and closed is provided in the opening 2 of the main body 1, and an operation panel 4 is provided. Operation panel 4
On the top are an oven key 6 for heating cooking, a temperature setting key 6 for setting the heating temperature, a timer volume 7 for setting the heating time, and a cooking start key 8.
．． A cancel key 8' is provided for clearing input data. 9 is a display window for displaying data set via the input means.

FIG. 2 is a block diagram showing the system configuration of the heating device. The operation panel 4 includes a control circuit 10 composed of a microcomputer or the like. Reference numeral 11 denotes a heating chamber, in which a tray 14 is placed on a saucer stand 13 that is rotationally driven by a motor 12 . A heat source, which is a plane heater 15, is installed at the upper and lower parts of the heating chamber 11, and heats the object 16 to be heated.

Further, an atmosphere thermistor 17, which is a sensor for detecting the temperature inside the refrigerator, is arranged on the side surface of the heating chamber 11, and when the temperature inside the refrigerator changes, the resistance of the atmosphere thermistor 17 changes. This change is transmitted to the control circuit 10, and when the set temperature input by the oven key 6 and set temperature key 6 on the operation panel 4 is reached, the flat heater 15 is turned on and off.
By doing so, the temperature inside the refrigerator is controlled to the set temperature.

This atmosphere thermistor 17 is covered with a cover 18 to protect it from dirt and damage.

First, we will explain how the calculation formula used in the present invention was derived.

FIG. 3 is a block diagram of the heating device used in the experiment. An object to be heated 16 is placed in the heating chamber 11, and a thermocouple 19 is installed above the object to measure the temperature inside the refrigerator. Based on the temperature measured by the thermocouple 19, the flat heater 16 as a heat source is controlled by the output control means 2°. Further, the thermistor 17 constantly displays the sensor level on the display means 21.

FIG. 4 is a chart when a cake is cooked at a setting of 160°C. (a) shows the time change in the temperature inside the refrigerator measured by the thermocouple 19. (b) is the heat source plane heater 1
5 shows the output state. (c) shows the time change of the sensor level read from the display means 21. A-Bl in each figure indicates a difference due to a difference in starting temperature within the heating chamber 11.

For humans, the heating chamber 11 is in a cold state, which corresponds to normal preheating, and the temperature inside the heating chamber 11 increases in the order of B to C.

As shown in FIG. 4(a), the heated object 16 is heated by the thermocouple 19.
Since the temperature is measured and controlled in the vicinity of , ideal control is achieved with no overshoot at any starting temperature.

The sensor level at that time is shown in the graph (c). In the broken line area, the control level L has not been reached, but the planar heater 15 as the heat source is operating.

Here, conversely, before the sensor level reaches the control level LK, the heat source flat heater 16 is turned on as in (c).
If it is possible to perform control that causes y, it should be possible to perform ideal control without overshoot as shown in (a). Looking at the graph (c), it can be seen that there is regularity in the sensor level ln (Il+, A2, 71s) at which the heat source is turned off. It sets the starting temperature, B,
The line connecting each A'+ and A2゜13 when changed like C is represented by a linear function. Although FIG. 4 is a characteristic diagram for cake cooking, similar results can be obtained for menus such as kutsky and choux. What was derived from this graph is In=Jo+Kn・(L
(Ao: lowest point level after cooking start, L: control level, N: constant). For example, in the human condition, the level Ill,71!2゜13 obtained by calculating the above formula from the initial level la is a value that can be approximated to the ideal value, and when the levels 11, A2, and A5 are reached, Heat source tlot2. By turning off for t3 seconds, a graph with no overshoot as shown in (a) is created. Similar experiments were conducted for B and C, but no overshoot occurred as in the case of M. Also, Mu, B,
Even at starting temperatures other than C, the above calculation formula An=10+K
1n (it, 12.1s) found by n・(L-1o)
are all on the straight line of the linear function mentioned earlier. The slope of the straight line between the two lines is set so that it becomes gentler as the times overlap.

Here, the larger n is, the more detailed control can be achieved, but OF
Since the number of times of F increases, the cooking time becomes longer. Although there were differences depending on the type of heating cooker, the best condition was that the cooking time was not long and the cooking time was about 3 to 5 times. In addition, the constant is a constant determined by the heated object 16 placed in the heating chamber 11, but in the case of automatic cooking, the constant is
It would be better to have a separate one for each menu, like a shoo, for more precise control, but with a normal manual heating cooker, you can get sufficient results even if you share it in each temperature range.

FIG. 6 is a chart showing the method of control in the case of setting at 150° C. in the present invention. Figure A shows the change in the atmospheric thermistor level over time, and Figure B shows the output state of the heat source. Figure 0 shows the change in temperature inside the refrigerator over time.

The control circuit 9 constantly reads the sensor level of the internal temperature detected by the atmosphere thermistor 17 after the start of cooking. Then, the sensor level lla at the time when the sensor level reached the lowest point is memorized and In=lo+K
Calculate n・(L −7!o) (n=−+, 2
．． 3).

Here, the lowest point sensor level L after lo uni-start:
Temperature control level Kn of the atmosphere thermistor = coefficient determined by the food As shown above, when the level of 7In determined by the calculation formula is reached, the tnn ripening heat source is turned on.In this example, with the setting at 160°C, Kn is + = 0.6, K2 = 0.84
.

Since there are three settings, K3 = 0.99, l+,
12. is three times each t1 = 9Q seconds, t2 = 9Q
seconds, t5 = 90 seconds, the heat source flat heater 16 is OFF
let

However, when the level of the atmosphere thermistor 17 reaches the temperature control level L, the control is immediately stopped and the conventional control of the atmosphere thermistor 17 is started.

However, when the cooking start temperature is high, such as immediately after preheating or during continuous use, that is, when lo is close to L within the range of lo<L, jh determined by the formula, A2. +
lls levels are close to each other. For example, L=100
, x,=o,7. K2=0.8, K3=O-9
In the case of 10=90, 11=97, J2=98
゜J3=99 and 12 during 11 seconds off of Nashi 11
O continuously for (t++t2) seconds after reaching the level of
FF is included, which causes overshoot in A5. To prevent this, the heat source is strongly turned on for 11 seconds after being turned off. According to experiments, this problem can be solved by turning ON for about t'=30 seconds.

In addition, in the case of continuous use, the first cooking temperature may be changed to 22.
When the second cooking temperature is low, la≧L and the sensor level is already above the temperature control level, so the heat source is off at the start. In such a case, if you stop the control when the temperature control level is reached as shown in Figure 4,
As shown in the figure, there will be overshoot, so la≧L
In this case, the multi-control is started when lo<. By doing this, overshoot as shown in FIG. 7 does not occur.

In addition, if the cooking is stopped by opening the door 3 or canceling after the cooking starts, and if the operation panel 4° temperature setting key 6
When the set temperature is changed, when starting cooking again, the control is not continued, but the lowest point level la is detected after the restart, since the temperature in the heating chamber 11 is the same as when it started with a high temperature. The above control is repeated.

By performing the above control, υ can be used with preheating, without preheating, in continuous use, or when the door 3 is opened in the middle.

Even in any case where the operation is interrupted due to a user's operational error such as pressing the cancel key 8, overshooting of the internal temperature can be prevented, and the optimal quality of the food can be provided.

Next, regarding the temperature range in which the above-mentioned control is performed, normally it would be fine to perform the control over the entire temperature range of the heating cooker, but there is also a problem with the capacity of the microcomputer in the control circuit 9, and even if there is overshoot, it will not be much of a problem. There are some menu items that do not affect the quality of the cake, especially sweets and cakes that are affected by overshoot.
If the operating temperature range for kutsky, choux pastry, etc. is limited to 150 to 180°C, the microcomputer capacity will be reduced.

Furthermore, although a heat source called a plane heater was used in the embodiment of the present invention, the present invention can be applied to any heating device such as one using a sheathed heater or one using a hot air circulation type.

Next, the control method of the present invention will be explained according to the flowchart shown in FIG. Open key -5 on operation panel 4
, Input the set time T using the temperature setting key 6 and the timer volume 7. ■ If the set time is input, the time t will be reset. ■ When the door 3 is closed [F], press the cooking start key. Enter the input and cooking will start.■, Set temperature is 1.
If 50°C≦set temperature≦18Q°C, the control of the present invention is started (■).

Thermistor sensor level at the same time as the start! The sensor level is read every 1 second. If the sensor level l is higher than the temperature control level L, the heater is turned on until l<L.
If NI, no Ca, l<L and the heater turns on, ■
, Compare the level 1 second after that point with the previous level, and if the level 0.1 seconds later is larger, set the previous level to 10 ■, If lo is detected, In = l
Calculate the Il level from a + Kn・(L-1a)■, If it becomes 1 level, ◎, turn on the heater for t1 second.
y [F], then pull out for t1 seconds - forcefully 3
0. Turn on for 0 seconds 0. Repeat this 3 times (2). When the set time is reached after 3 times, cooking ends (2). When 150°C≦set temperature≦180°C, control is performed using the conventional method. If this control center shrine counts up and the door opens to 0, ■
If you press the Cancel key manually, it will return to ■. Moreover, if the thermistor level becomes l≧I, the process goes to (2) and performs conventional control. ■ is constant (however, it does not go to ■ only if A>L after cooking starts)
.

Effects of the Invention From the above explanation, according to the present invention, the following effects can be obtained.

0) Using the detection level of the sensor that controls the internal temperature, the microcomputer turns on the heat source.

Since it is characterized by being turned off, it not only eliminates overshoot, but also allows you to freely control the temperature inside the refrigerator.

For example, it is possible to control the first half of cooking at a low temperature and the second half at a high temperature.

Therefore, it is very effective not only for conventional open ranges but also for automatic cooking devices and the like because it allows for more detailed control.

(2) Regardless of the starting temperature, such as preheating, no preheating, high temperature start, or continuous use, it is possible to eliminate overshoot of the internal temperature and provide optimal food quality.

(3) Overshoot can be improved using only a conventional atmosphere thermistor without using a new sensor such as a surface thermistor, resulting in cost reduction.

In addition, surface thermistors are susceptible to external factors such as wind and are restricted in their installation location, whereas atmosphere thermistors are located inside the refrigerator, making them extremely stable and unaffected by external factors. Since control is performed using the stable level of the atmosphere thermistor, extremely reliable control can be performed.

(4) When the lowest point level flo is close to the temperature control level L, the lowest point level flo is close to the temperature control level L by stopping the heat source for a certain period of time and then forcibly turning on the heat source for a certain period of time. Even if the OFF time is long, overshoot can be prevented.

(5) A line connecting each point at which the power supply to the heating source is first stopped in a plurality of time-lapse characteristic curves of temperatures detected by the temperature sensing means starting from different initial temperatures is substantially By controlling the heating source so that it is placed at a position represented by a linear function, calculations in the control circuit can be performed extremely easily.
The storage capacity involved in calculations can also be extremely small.

(6) Furthermore, the above configuration has fewer constants that change depending on the type of food to be cooked, and in this sense also requires less storage capacity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main body showing an embodiment of the present invention, FIG. 2 is a block diagram showing the system configuration, and FIG. 3 is a block diagram showing the system configuration of an experiment conducted to derive a calculation formula.
FIG. 4 is a time chart showing the sensor level of the internal temperature and the output state of the heat source, and FIG. 5 is a sensor flowchart of the heating device according to an embodiment of the present invention. 1...Main body, 4...Operation panel, 5.
...Open key, 6...Temperature setting key, 10...Control circuit, 11...Heating chamber, 16...Heated object, 17... Atmosphere thermistor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3? O Figure 4 Figure 5 Figure 6 - 111 Figure 7 Figure 1 → and Figure 8

Claims (10)

[Claims] (1) On the front of the main body, there is a control section equipped with a display device, a means for setting the heating function, a means for setting the heating temperature, a means for setting the heating time, etc., and a heating chamber in which the object to be heated is stored inside the main body. and a heat source for heating the object to be heated in the heating chamber, a sensor for detecting the internal temperature of the heating chamber, and a control circuit for controlling the internal temperature based on the level detected by the sensor. After the start,
The level l is determined by adding to the lowest level l_o detected by the sensor a value obtained by subtracting the l_o from the temperature control level L of the sensor multiplied by a food-specific coefficient K determined by the food. The heating device is configured to stop the heat source for a certain period of time to eliminate overshoot of the temperature inside the refrigerator. (2) The heating device according to claim 1, wherein when the temperature reaches the L level, the heat source is stopped for a certain period of time, and then the heat source is forcibly turned on for a certain period of time. (3) Coefficient K at least twice (0.01<K_1
The heating device according to claim 1, wherein the heating device is provided a plurality of times such that <K_2<...<K_n<0.99). (4) Turning off the heat source using the coefficient K ends when the level of the sensor reaches the temperature control level L, and then,
The heating device according to claim 1, wherein the temperature inside the refrigerator is controlled by the temperature control level L of the sensor. (5) The heating device according to claim 1, wherein after the start of cooking, the level l_o is detected again when the cooking is interrupted due to opening of the door or cancellation, or when the set temperature is changed and the cooking is restarted. (6) After the start of cooking, if the sensor detection level is equal to or higher than the temperature control level L, the heat source is turned on and then the level l_
The heating device according to claim 1, wherein the heating device is configured to detect o. (7) The heating device according to claim 1, wherein the control is configured to be used within a certain temperature range within the settable temperature range. (8) A heating chamber that accommodates an object to be heated, a heating source that increases the temperature inside this heating chamber, a temperature detection means that is provided in a part of the heating chamber and that detects the temperature inside this heating chamber, and a heating condition that detects the temperature inside the heating chamber. an operation setting means for setting, a control means for controlling the operation of the heating source based on information from the operation setting means and the temperature detection means; A point at which the line connecting each point at which power supply to the heating source is first stopped is substantially represented by a linear function in a plurality of time-lapse characteristic curves of temperatures detected by the temperature sensing means starting from A heating device configured to control the heating source so that the heating source is installed in the heating device. (9) After the operation of the heating source, the control means is configured to determine, in a plurality of time-lapse characteristic curves of temperatures detected by the temperature sensing means starting from different initial temperatures, each of the second and third times when the power supply to the heating source is stopped. 9. The heating device according to claim 8, wherein the heating source is controlled so that the points and the lines connecting the points are also arranged at positions represented by linear functions. (10) The control means is configured to control the heating source so that the slope of the straight line connecting the points of each of the second and third times when power supply to the heating source is stopped becomes gentler as the times overlap. 9. The heating device according to 9.