JPS6142170B2

JPS6142170B2 -

Info

Publication number: JPS6142170B2
Application number: JP11521780A
Authority: JP
Inventors: Shigeru Kusuki; Keijiro Mori
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1980-08-20
Filing date: 1980-08-20
Publication date: 1986-09-19
Also published as: JPS5741525A

Description

[Detailed description of the invention]

本発明は、オーブン機能を有する加熱器の自動
化に関するものである。従来は、食品の種類と量
に応じて、経験と勘により、オーブン加熱の温度
と時間を設定していたが、過加熱や不足加熱にな
ることが少なくなかつた。本発明は、センサを用いることにより上記従来
の欠点を解消するものである。解析実験をするこ
とで、オーブンで加熱をすると温度やHC系のガ
ス（特に炭素Ｃの値が１価、２価の例えばメタノ
ールCH₄、エタノールC₂H₆の如きガス）が加熱
の進捗度合や量に応じて発生することを知つた。
一方上記ガスに感じる素子として、電気ヒータで
センサを傍熱したもの、例えばSnO₂に触媒を添
加したものや、MgCr₂O₄−TiO₂系の材料の焼結
体がガス量に応じて抵抗値が変化することを知ら
れている。本発明は上記ガス検知器の信号に基づいて、制
御処理に工夫を加えることによりオーブンの自動
化をはかることを目的とする。以下本発明の一実施例について、第１図〜第５
図に基づいて説明する。第１図は本発明オーブン
構成の一実施例である。１は加熱室、２はヒー
タ、３は被加熱物、４は被加熱物を載置する皿で
ある。５は加熱室壁、６は加熱室壁の一部に開孔
を施こした通気孔、７は通気孔からの気体を装置
外に排出するための排気ダクト、８は排出気体中
の湿度や、HC系の量により抵抗値が変化する検
知素子（以下センサと称す）、９はオーブンケー
ス、１０は脚である。第２図は、センサの抵抗値Ｒが時間ｔとの関係
で変化する特性図の一例を示す。このセンサは、
高温になると抵抗値が小さくなる変化をし、ガス
や湿度の量が増加すると抵抗値が大きくなるもの
を例にした。図中はオーブンの予熱期間である。食品がな
い状態で約250℃で約15分程度加熱をする。この
間では、排気温度が高くなるので、前述のセンサ
の特性から抵抗値は下がる。次に食品を入れる。
図中は、食品を庫内に入れてから一定時間経過
するまでの期間である。本発明で用いたセツトで
は、この時間を４分を中心に数種変えてみた。こ
の期間では食品からガスが発生しはじめるので抵
抗値は上昇しはじめる。はの終了後、加熱完
了までの期間である。この期間では、ガス発生が増加しつづけるので
抵抗値は上昇する。食品をマドレーヌケーキの
（初期重量約420ｇを７つのカツプに分けて同時加
熱する）場合は、期間，を合わせて18分、約
250℃のオーブン雰囲気で加熱をすると程良い出
来上りになることを確認している。第３図は、食品の量を変えたときのセンサの抵
抗値の時間変化例を示す特性図、Ｎは食品の量を
示す。ΔＲ，ΔR₁，ΔR₂，ΔR₃は、期間での
最低抵抗値又は、期間の開始時点の抵抗値（こ
れを基準の抵抗値Rsと呼ぶ）と、期間の終了
時点での抵抗値との差を示す。食品の量を増加す
ると、表面積も増加し、したがつてガス発生量が
増加する。１個当り420／７＝60ｇのケーキを例
に、期間を４分に設定したときの抵抗値の例を
下に示す。 The present invention relates to automation of a heater with oven function. Conventionally, the oven heating temperature and time were set based on experience and intuition depending on the type and amount of food, but this often resulted in overheating or underheating. The present invention eliminates the above-mentioned conventional drawbacks by using a sensor. By conducting analytical experiments, we found that when heating in an oven, the temperature and HC gases (especially gases with monovalent or divalent carbon C values, such as methanol CH ₄ and ethanol C ₂ H ₆ ) can be changed to determine the degree of heating progress. I learned that it occurs depending on the amount and quantity.
On the other hand, as an element that senses the above gas, a sensor that is indirectly heated with an electric heater, such as one that has a catalyst added to SnO ₂ or a sintered body of MgCr ₂ O ₄ -TiO ₂ based material, has a resistance that changes depending on the amount of gas. The value is known to change. An object of the present invention is to automate the oven by adding a device to the control process based on the signal from the gas detector. An embodiment of the present invention will be described below in Figures 1 to 5.
This will be explained based on the diagram. FIG. 1 shows an embodiment of the oven configuration of the present invention. 1 is a heating chamber, 2 is a heater, 3 is an object to be heated, and 4 is a plate on which the object to be heated is placed. 5 is a heating chamber wall, 6 is a ventilation hole made in a part of the heating chamber wall, 7 is an exhaust duct for discharging the gas from the ventilation hole to the outside of the device, and 8 is a ventilation hole for removing humidity in the exhaust gas. , a detection element whose resistance value changes depending on the amount of HC system (hereinafter referred to as a sensor), 9 an oven case, and 10 a leg. FIG. 2 shows an example of a characteristic diagram in which the resistance value R of the sensor changes with respect to time t. This sensor is
As an example, the resistance value decreases as the temperature increases, and increases as the amount of gas or humidity increases. The figure shows the oven preheating period. Heat at about 250℃ for about 15 minutes without food. During this period, the exhaust temperature increases, so the resistance value decreases due to the sensor characteristics described above. Next, add the food.
The figure shows the period from when food is placed in the refrigerator until a certain period of time has elapsed. In the set used in the present invention, this time was varied several times, mainly 4 minutes. During this period, gas begins to be generated from the food, so the resistance value begins to rise. This is the period from the end of heating to the completion of heating. During this period, the resistance value increases as gas generation continues to increase. When making a madeleine cake (initial weight of about 420g divided into 7 cups and heated at the same time), the total time is 18 minutes, about
We have confirmed that heating it in an oven atmosphere at 250℃ produces a good result. FIG. 3 is a characteristic diagram showing an example of how the resistance value of the sensor changes over time when the amount of food is changed, and N indicates the amount of food. ΔR, ΔR ₁ , ΔR ₂ , ΔR ₃ are the lowest resistance value in the period, or the difference between the resistance value at the start of the period (this is called the reference resistance value Rs) and the resistance value at the end of the period. Show the difference. Increasing the amount of food also increases the surface area and therefore gas production. An example of the resistance value when the period is set to 4 minutes is shown below, taking a cake weighing 420/7 = 60g per piece as an example.

【表】第４図にはＮ＝２のときのΔR₂を基準に、n₂
＝ΔＲ／ΔR₂と個数Ｎの関係を示す特性例を示
す。図をみれば、ガスや湿度の発生による抵抗Ｒ
の変化量が個数（食品の量）とほぼ比例関係にあ
ることがわかる。このことは、一定基準量（ケー
キ７個）の適正加熱時間Ｔ（約18分）が分つてお
れば、食品加熱開始後一定時間Ts（４分）後に
必要な加熱時間Ta（７個のとき約14分）との関
係を例えばＴ＝Ts＋TaをＴ＝（１＋kn）Tsとい
う形で加熱時間を設計すれば（ｎは個数や量の関
数、ｋは食品の種類に応じてきまる定数とする）
食品の量が変化しても一定の仕上がり状態にでき
る。マドレーヌケーキの場合ｋは3.5、７個のと
きのｎを１とすると、各種は次の如くなる。 _[ Table] Figure 4 shows n 2 based on ΔR ₂ when N = 2.
A characteristic example showing the relationship between =ΔR/ΔR ₂ and the number N is shown. Looking at the diagram, we can see that the resistance R due to the generation of gas and humidity
It can be seen that the amount of change in is almost proportional to the number of pieces (amount of food). This means that if the appropriate heating time T (approximately 18 minutes) for a certain standard amount (7 cakes) is known, the required heating time Ta (for 7 cakes) after a certain time Ts (4 minutes) after the start of food heating is known. For example, if we design the heating time using the relationship T=Ts+Ta as T=(1+kn)Ts (where n is a function of the number or amount of food, and k is a constant that varies depending on the type of food).
Even if the amount of food changes, the finished product can remain constant. Assuming that k is 3.5 for madeleine cakes and n is 1 when there are 7 cakes, the various types are as follows.

【表】従つて７個を標準（ｎ＝1.0）とした関係（ｋ
＝3.5）を設計時に決めてやれば個数Ｎが変化し
ても加熱時間Ｔが自動的に修正できるものであ
る。第５図は、自動オーブン調理をするための制御
回路ブロツク図の例である。１１は検知素子の抵
抗変化をブリツジ回路等で電圧変化に変える変換
回路、１２は変換回路１１の電圧を増巾する電圧
増巾器である。１３は、電圧記憶回路で基準抵抗
値Rsに相当する電圧を記憶する。１４は、記憶
された電圧値と電圧増巾器１２の出力の差でΔＲ
に相当する電圧値に処理する差動増巾器である。
１５は、時間処理回路であり、基準量に応じた定
数ｋと基準量のΔＲに相当する定数ΔRsを設定
された食品に応じて電圧発生し、差動増巾器１４
からの測定された加熱開始後一定時間Ts後に測
定したΔＲの値に相当する電圧との間に、Ta＝
（ΔＲ（測定値）／ΔＲｓ（定数）×ｋ）×Tsなる量を
計算する機能をもつ。１６はヒータ制御回路で時間処理回路１５
の信号で加熱終了の信号を矢線１８を通してヒー
タ（図示せず）に送る。１７は、加熱開始時点
で、基準抵抗値Rsを記憶するタイミング信号を
送る矢線である。以上のように本発明の構成によれば、食品に応
じた基準量ｋ，Ts、を設定すれば、量が変化し
ても自動的に適正仕上がりに調理できるもので、
非常に操作性が向上する。上記説明は、センサとして温度特性を有し、湿
度やガスの発生では抵抗性が上昇するものを用
い、また抵抗値変化をブリツジ回路で電圧変換す
る例を示して行なつたが、抵抗値の変化が逆のセ
ンサを用いてもよく抵抗変化を固定コンデンサと
の組合わせで、周波数変換でもよいことは云うま
でもない。さらに上の説明では、食品の加熱開始時点で基
準信号を記憶させた例を示したが、変化特性の変
曲点での値、第２図におけるセンサ抵抗の最低値
を基準として記憶する場合も本発明は含む。[Table] Therefore, the relationship (k
= 3.5) at the time of design, the heating time T can be automatically adjusted even if the number N changes. FIG. 5 is an example of a control circuit block diagram for automatic oven cooking. Reference numeral 11 represents a conversion circuit that converts a change in resistance of the sensing element into a voltage change using a bridge circuit or the like, and reference numeral 12 represents a voltage amplifier that amplifies the voltage of the conversion circuit 11. 13 is a voltage storage circuit that stores a voltage corresponding to the reference resistance value Rs. 14 is the difference between the stored voltage value and the output of the voltage amplifier 12, ΔR
This is a differential amplifier that processes voltage values corresponding to .
15 is a time processing circuit, which generates a voltage according to the food for which a constant k corresponding to the reference amount and a constant ΔRs corresponding to ΔR of the reference amount are set, and the differential amplifier 14
Ta=
It has a function to calculate the amount (ΔR (measured value)/ΔRs (constant)×k)×Ts. 16 is a heater control circuit and a time processing circuit 15
A signal indicating the end of heating is sent to the heater (not shown) through the arrow 18. Reference numeral 17 indicates an arrow line that sends a timing signal to store the reference resistance value Rs at the time of starting heating. As described above, according to the configuration of the present invention, if the reference amounts k and Ts are set according to the food, even if the amounts change, the food can be cooked to an appropriate finish automatically.
Operability is greatly improved. The above explanation uses a sensor that has temperature characteristics and whose resistance increases when humidity or gas is generated, and uses a bridge circuit to convert changes in resistance value into voltage. It goes without saying that a sensor with the opposite change may be used, and the resistance change may be combined with a fixed capacitor to perform frequency conversion. Furthermore, in the above explanation, an example was shown in which the reference signal was stored at the start of heating the food, but the value at the inflection point of the change characteristic or the lowest value of the sensor resistance in Figure 2 may also be stored as the reference. The present invention includes.

[Brief explanation of the drawing]

第１図は本発明の自動オーブンの一実施例を示
す構成図、第２図は本発明で用いたセンサ抵抗値
の時間変化例を示す特性図、第３図は食品の量を
変えたときのセンサ抵抗値の時間変化例を示す特
性図、第４図はセンサ抵抗値の差ΔＲの比ｎと食
品量との関係例を示す説明図、第５図は本発明で
用いた制御回路構成の一実施例を示すブロツク図
である。１……加熱室、８……センサ、１５……時間処
理回路、１１〜１８……制御回路を構成、Rs…
…予熱完了後の基準抵抗値、Ｒ……測定時点での
抵抗値、Ts……加熱開始後の一定期間。 Fig. 1 is a configuration diagram showing an embodiment of the automatic oven of the present invention, Fig. 2 is a characteristic diagram showing an example of the change in sensor resistance value over time used in the present invention, and Fig. 3 is a diagram showing the change in the amount of food. FIG. 4 is an explanatory diagram showing an example of the relationship between the ratio n of the sensor resistance difference ΔR and the amount of food, and FIG. 5 is a control circuit configuration used in the present invention. FIG. 2 is a block diagram showing one embodiment of the invention. 1...Heating chamber, 8...Sensor, 15...Time processing circuit, 11-18...Configuring control circuit, Rs...
...Standard resistance value after completion of preheating, R...Resistance value at the time of measurement, Ts...A certain period of time after the start of heating.

Claims

[Claims] 1. In an oven that heats food by increasing the ambient temperature of a heating chamber, in the heating chamber or in an exhaust duct connecting the heating chamber and outside air,
Equipped with a sensor whose resistance value changes depending on humidity and gas,
A time processing circuit calculates the difference between the reference resistance value of the sensor after the completion of preheating and the resistance value after a certain period of time after the start of heating with a constant depending on the food,
An automatic oven characterized by having a control circuit that determines the necessary heating time. 2 Selecting the constants of the time processing circuit according to the food,
The automatic oven according to claim 1, wherein the automatic oven is configured so that manual settings can be made from outside the oven.