WO1983000374A1

WO1983000374A1 - Heater with sensor

Info

Publication number: WO1983000374A1
Application number: PCT/JP1982/000272
Authority: WO
Inventors: Ltd. Matsushita Electric Industrial Co.
Original assignee: Watanabe, Kenji; Akiyoshi, Mitsuo
Priority date: 1981-07-20
Filing date: 1982-07-16
Publication date: 1983-02-03
Also published as: JPS5813925A

Abstract

When the initial temperature of a heating chamber is high, the variations in the relative moisture detected by a moisture sensor (10) are reduced, by, for example, the reaction with vapor from food, if the sensor (10) reacts with the vapor. Accordingly, there is a problem of providing a sufficiently high sensitivity when steam is produced from the food being heated. This heater with a sensor varies the value which determines whether the food has been heated by comparison with the value detected by the sensor (10), and a constant for determining the total heating time according to the initial temperature of the heating chamber, thereby enabling an effective automatic cooking of food even regardless of the atmosphere in the kitchen.

Description

Specification

Title of invention ''

Heating device with sensor

Technical field

The present invention relates to an improvement in means for detecting a heating state and means for determining a total heating time in an automatic heating device provided with a sensor. Background art

In recent years, remarkable progress in semiconductor technology has succeeded in increasing the functionality of control circuits, reducing the size due to a high degree of bond collection, and reducing the price due to mass production effects, and these electronic control circuits have become widely used in home electric appliances. .

Various heating devices, such as electric ovens, electronic rangers, gas ovens, or composite products of these, have been rapidly becoming intelligent based on this electronic control. A particularly troublesome problem with the heating device is that the automatic heating device, which detects the heating state of the powder to be heated by means of various sensors and automatically controls the heating, quickly penetrated. . -'This is because, even if the user does not set the heating time, output, heating temperature, etc. as in the past, the control unit automatically ends the heating using the sensor. With an electronic range that requires consideration of the quantity of the material and the initial temperature, etc., it has been made possible to perform a simple soldering operation and to perform heating with few failures.

As such prior art, there is Japanese Patent Application Laid-Open No. 51-34995. This detects a change in humidity generated from the object to be heated, and the point when the change reaches a certain set value is defined as a steam generation point. And heating time T ¹ of the to reach there, the heated object-specific coefficients R are separately prescribed • the sum of the pickles RT ¹ of it is an total heating time.

This is an example of automatic heating control using a so-called humidity sensor, but is also an effective control method for a so-called gas sensor that reacts to steam, alcohol, and carbon dioxide. Just in this method

5 also had the following difficulties. In other words, if the temperature in the heating chamber increases, the relative humidity decreases and the drying chamber becomes dry, so that the humidity sensor and gas sensor that react to steam will have lower detection levels and will be heated. Even when vapors began to come out of the object, the sensitivity was low enough compared to low temperatures.

1 ₀ Figure 3 is an example showing plainly such situations. First, [ ¹ ] in the case where heating is started when the heating chamber is at room temperature will be described. In the initial stage of heating, the temperature inside the heating chamber gradually increases depending on the heating source, so that the relative humidity RH in the heating chamber decreases. Rollers increases the temperature of the heated object is eventually the generation of steam actively ¾ connexion is rather that the (P ¹ point), overcoming the reduced convex 'Ku of RH relative humidity to the temperature rise of the heating chamber However, the relative humidity RH shows an increasing tendency. The point at which the humidity rises above a certain threshold, Ρ2, is defined as the steam generation point, and the sum of the heating time required to reach that point and the separately determined picking coefficient 称 specific to the heated object The concept of Japanese Patent Application Laid-Open No. Sho 51-13495 is to set the total heating time to zero.

However, when heating is started at a high temperature so that the temperature in the heating chamber exceeds 50 ([ ² ]), the relative humidity RΗ has dropped considerably from the beginning of the heating, that is, the end is dry. Even if the same amount of water vapor as that of D is generated from the object to be heated, the relative humidity is as large as [ ¹ ].

25 Humidity does not change. Room temperature 20 ° C, relative humidity according to humidity

BUf? At 40%, if the temperature in the heating chamber has risen to 50 ° C, then the relative humidity in the heating chamber will drop to 1 o%. In this state, it is assumed that 1 O ^ water vapor is generated from the object to be heated. At this time, if the temperature in the heating chamber is 2 o ^e c, which is the same as the temperature, the relative humidity will be 1 oo%, that is, it will reach a saturated state, but if it rises to 50 ° C

Only up to 20%. That is, in [ ¹ ], the relative humidity changed by as much as 60%, and in [ ² ], the relative humidity changed only by 1%. Therefore, if the steam generation point P ² 'is detected at a certain threshold value, it will be delayed compared to the point Ρ2. Therefore, the heating time is too long, resulting in overheating.

The remainder of the total change with respect to the threshold value: the degree is small, and the sensitivity is high.

DISCLOSURE OF THE INVENTION-In view of such a background, the present invention provides an automatic heating device that realizes stable and reliable automatic heating without the presence of a temperature in a heating chamber.

¾)

In order to achieve the above object, the present invention relates to the following: (1) When the initial temperature of the heat chamber is high, the amount detected by the sensor in the sensor reacting to steam is reduced, and thus the amount detected by the sensor is reduced. In this configuration, a predetermined value for judging the heating state by comparison and a constant for determining the total heating time are changed according to the initial temperature of the heating chamber. Therefore, regardless of the temperature at the start of heating in the heating chamber, the humidity sensor can detect the slight amount of water vapor generated from the object to be heated, preventing the failure of automatic ripening cooking. Then, it is possible to perform automatic heating cooking with a good finish. — —

Brief description of drawings

FIG. 1 is an external perspective view of an automatic heating device according to an embodiment of the present invention, FIG. 2 is a block diagram of the same configuration, and FIG. 3 shows a change in relative humidity in a heating chamber in a conventional heating device. Fig. 4 schematically shows the control method, Fig. 4 is a diagram showing a control method which is an example of the present invention, and Fig. 5 shows a control method which is another embodiment of the present invention. Figure 6 shows the actual sensor! 5) Diagrams showing detected voltage waveforms, where (a) shows a humidity sensor and (b) shows a gas sensor. FIG. 3 is a functional block diagram of the control unit.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the configuration of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of the main body of the automatic heating device according to the present invention. A door 2 is attached to the front of the main body 1 so as to be openable and closable, and an operation panel 3 is provided. The operation panel 3 is provided with at least a keyboard 4 for selecting a heating sequence in accordance with an object to be heated, and a display unit 5 for performing various notifications. -Figure 2 shows a control block diagram of such a heating device. An object 7 to be heated is placed in the heating chamber 6, and a magnetron 8 is connected as a heating source. The power of the magnetron B is controlled by the control unit 9. Details of the control unit 9 ¾ The configuration will be described later. C 1 O is a humidity sensor or a gas sensor, and the water vapor and the air discharged from the object to be heated exhausted by the fan 11 Gas, charcoal gas, etc. which gas 12 is detected. 13 is a temperature detecting means such as a thermistor for measuring the temperature in the heating chamber. Based on the detected data, the enemy unit 9 controls the power supply to the magnetron ⁸ and sends some data to the display city 5. Display various warnings and warnings with a synthesized voice or a buzzer sound using the speaker or buzzer 14.

Now, the operation of the control unit 9 with such a configuration will be described. Fig. 3 of the conventional method has already been described. The point is that even when the same amount of water vapor is generated from the same object to be heated, the amount of change in the relative humidity varies greatly depending on the temperature in the heating chamber at that time. The present invention monitors the temperature in the heating chamber, thereby stably and surely ascertaining the point at which steam or gas is generated, and realizes automatic heating by a sensor that depends on the temperature in the heating chamber.

FIG. 4 is a diagram showing a method for detecting a steam generation point based on the present invention. The control unit 9 first measures the temperature in the heating chamber using the thermistor 13. By performing through such measurements are total heating time, the but of course that it is precisely ¾ control, also measured at any single point of heating start point or P ¹ point, or vapor generated point P ² points even rather small ¾ The purpose of the explanation can be reached. -Now, based on the temperature measured in this way, the control unit 9 resets a threshold value corresponding to the temperature in the system. In other words, in the case of [ ¹ ], the threshold value “2” is smaller than that in the case of the higher temperature [ ² ]. As a result, the steam detection points Ρ2 and The P ² 'point can be matched, so that the total heating time can be determined stably irrespective of the temperature, and there is sufficient margin between the threshold value and the amount of change at high temperature, and the sensor You can prevent insensitivity.

In this example, regardless of the temperature inside the heating chamber, • Although the total heating time can be determined stably by the amount of, the object to be heated is supplied with heat energy from this ambient temperature if the temperature inside the heating chamber is high. For this reason, the total heating time is rather short. This can be achieved by setting 《 ² less than ^^. That is, the point of D vapor generation point P ² 'point in Fig. 4] is also taken earlier, so that the time can be shortened and the total heating time can be shortened and corrected.

However, when the sensor characteristics are such that the sensitivity decreases at the contact end at high temperatures, the change in relative humidity is very small as shown in Fig. 5. Is there a limit to reducing the threshold i? In the case of 3, it is impossible to match point P ^{2 with} point P. Therefore, T ¹ hour is too long and the heating is tight. Therefore, the constant H that determines the total heating time can be reduced, and overheating can be prevented.

15 Another embodiment is shown below. In a region where the temperature of the heating chamber has a sufficient margin between the threshold value and the amount of change, it is not necessary to change the threshold value. The time may be corrected. Constant B is a constant peculiar to food. JD. It can be selected even when the heating chamber is at high temperature.

20 ¾ 1) The total heating time can be more stable.

Furthermore, when the temperature in the heating chamber becomes high, for example, in a combined heating device of an electro-mature heater and a microphone mouthpiece, so-called oven range, the temperature in the heating chamber immediately after the use of a heater flight is 2 5 0 to 3 0 Q ^e is reached in C, but the threshold is g Umate small value DOO Ru in such a state. If the sensor or its detection circuit receives noise, — T —

• Get it. Therefore, in the present invention, the temperature at which the sensor or its detection circuit becomes ineffective is determined as a hot level, and the hot level at the time of temperature measurement by a thermistor is detected. If a heating circuit is started, or if heating is in progress, a power supply to the heating source is stopped, and a safety circuit is provided to stop ripening. The inability of the sensor is notified to the user by a display on the display means or a notification of the synthesized voice to the speaker 14 by the voice synthesis means.

FIG. 6 shows the voltage waveform of the sensor detection voltage S 1 actually detected by the sensor, where (a) shows the humidity sensor and (b) shows the gas sensor. The relative humidity R H detected by the humidity sensor is

Showing the same changes as described in Figure 4) |), there is nothing to add. For gas sensors, this graph is a direct reading of the change in sensor impedance, but at high temperatures the change in the detected value is small because the change in relative humidity is small. You can see that it is small. Therefore, if the threshold value is controlled according to the temperature of the heating chamber as in the present invention, good automatic heating can be realized.

The threshold value may be an absolute value as in this embodiment,

It may be a relative value such as a voltage ratio between Ρ ¹ point and Ρ ² point.

Now, how to implement the control method as described above, the specific configuration of the control unit will be described in detail below. FIG. 4 is a block diagram showing a functional configuration of the control unit 9. Se emissions Sa 1 Anal port grayed amount I detected in Ο is converted to Dejitanore amount by the AZD converter 1 5, is input to the V ¹ detector ^{1 6} and leveled Noreko damper rater ¹ 7. V ¹ detector 1 6 is a block to detect the leveling Norre of P ¹ point, humidity • Detects the minimum value from the temperature sensor and the maximum value from the gas sensor.

V ¹ holding register 1 S is restored. Specifically, detector 16

Read First, the value of V ¹ holding register 1 S, responsible for the update of the p V ¹ value to the V ¹ holds Les Soo data 1 8 by a comparison of the new data.

On the other hand, the thermistor ¹³ measures the temperature in the heating chamber, and the AZD converter 19 is used for the measurement! ? Input as the amount of data. The converter 19 converts this into a digital storage amount TMP, reads out the corresponding useful n from the register 21 by means of the selector 20 and reads the corresponding useful n from the register 21, and reads the value from the register 21. Enter 7 The controller 19 also has a function of detecting an unsensorable level and outputs a HOT signal.

By the way, the level comparator 1 is

'Compare the obtained sensor information with the above-mentioned V ¹ value, and determine whether or not the predetermined threshold value _η input from the selector 20 has been _exceeded .

5 That is, Ρ two points are detected.ぱ When 2 points are reached ぱ HD signal

Power.

When the HD Τ signal is output, clock counting by the web counter 22 stops. And § Tsu Buka cormorant printer 2 2 by connexion counted time, the multiplier 2 3 input of additional heating time Rn'T ¹ to

0 Calculated and set 24 downcounters.

The value corresponding to the combination of the menu selected by the keyboard ⁴ and the value TMP obtained by converting the temperature in the heating chamber into a digital amount is stored in the R register 26 by the R selector 25. The signal is extracted and input to the multiplier 23.

5 On the other hand, the power supply to the magnetron S is pressed by the start key _

OMPI • Immediately after being started by a flip-flop. Reference numeral 28 denotes a drive circuit for operating the magnetron 8. The flip-flop 27 shifts to the additional heating mode, and when the content of the down counter 24 is detected at the outlet: 5: Detachment is detected by the decoder 29]. i 5 Chi P ² points by Rn -. when the T i time has elapsed, terminate the heating is Bok by re set to ZERO signal. The time of AZD co Nba over data ¹ 9, I H 0 T signal is output, even when the temperature of the to Wachi heating chamber exceeds the sensor impossible level, full re Tsu Pufu Lock flop 2 7 Resets and prohibits or interrupts heating.

The HOT signal is also input to the display unit 5 and the synthesizer S0 as a voice synthesizing unit, and a warning is issued to the user in the form of a display and a synthesized voice.

As described above, the present invention can be realized by the control unit shown in FIG. In addition, each function block in Fig. 7 can be replaced by software-based software logic, and most of the functions are implemented by a micro-computer female storage logic controller. ¾It is natural that we can do it.

Industrial applicability

As described above, according to the present invention, an automatic heating apparatus having a stable and reliable sensor independent of the temperature in the heating chamber can be realized. Also, even at high temperatures, the margin between the threshold value and the total variation can be sufficiently provided, and sensor confusing can be prevented. Therefore, it can be widely used in heating cookers such as microwave ovens and electric ovens.

0Λ1ΡΙ

Claims

The scope of the claims

A heating chamber on which the object to be heated is placed; a heating source coupled to the heating chamber; a control unit for controlling power supply to the heating source; water vapor generated by the object to be heated; A sensor for detecting a throat, temperature detecting means for measuring the temperature of the heating chamber, and the sensor! ? Comparison means for comparing the detected amount with a certain predetermined value; and time control means for determining the time for continuous heating after the amount detected by the sensor reaches a certain predetermined value by a certain constant. The control unit is configured to determine a reference value of the comparison unit and the time control in accordance with the temperature of the heating chamber detected directly or indirectly by the temperature detection unit. A heating device provided with a sensor characterized in that a constant that determines a heating time is changed in a section.

2. The heating device according to claim 1, further comprising a sensor that changes only a predetermined value that is a reference of the comparison unit.

Claim 1. The heating device according to claim 1, further comprising a sensor characterized in that only the constant for determining the heating time is changed by the time control unit.

In claim 1, when the temperature detecting means measures that the temperature of the heating chamber is high, the control unit changes the reference value of the comparison unit to a smaller value. A heating device equipped with a sensor.

In claim 1, according to the temperature detecting means] 3 The control unit classifies the temperature of the heating chamber into at least three levels, and the highest level threshold substantially matches the level at which the sensor cannot be used. Let the temperature 5. The sensor according to claim 4, further comprising a sensor characterized in that the control unit prohibits or interrupts the supply of electric power to the heating source when a level is detected. A ripening apparatus provided with a sensor that is provided with a display means for notifying the user or a notification means such as a voice synthesis means.

WiPo