JP2714812B2 - Boiling point detection method - Google Patents
Boiling point detection methodInfo
- Publication number
- JP2714812B2 JP2714812B2 JP63108825A JP10882588A JP2714812B2 JP 2714812 B2 JP2714812 B2 JP 2714812B2 JP 63108825 A JP63108825 A JP 63108825A JP 10882588 A JP10882588 A JP 10882588A JP 2714812 B2 JP2714812 B2 JP 2714812B2
- Authority
- JP
- Japan
- Prior art keywords
- boiling point
- temperature
- liquid
- temperature sensor
- detection method
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Investigating Or Analyzing Materials Using Thermal Means (AREA)
- Cookers (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、ボイラーやジャーポット等に用いられる沸
騰点検出方法に関する。Description: TECHNICAL FIELD The present invention relates to a boiling point detection method used for boilers, jar pots, and the like.
（従来の技術） 従来、液体加熱装置は一般に、第４図に示すように液
槽の一部に設置された温度センサー３からの信号が、A/
D変換器内蔵のマイクロ・コンピューターを中心にリレ
ー等から構成された温度制御器５に入力され、得られる
出力によってヒーター４が通電され、液槽１中の液体２
が加熱される。(Prior Art) Conventionally, a liquid heating apparatus generally receives a signal from a temperature sensor 3 installed in a part of a liquid tank as shown in FIG.
A heater 4 is energized by a temperature controller 5 composed of a relay or the like with a microcomputer having a built-in D converter as a center, and the liquid 2 in the liquid tank 1 is turned on.
Is heated.
このような液体加熱装置の沸騰点検出方法は、第５図に
示す如く、温度センサーの温度が所定の温度を越える
と、一定温度ΔＴだけ上昇するのに要する時間を測定し
沸騰点検出の測定を開始する。即ち同図に於いて、沸騰
点よりずっと低い温度では一定温度ΔＴ上昇するのに要
する時間t1,t2，……tnは短いが、沸騰点に近づくと所
要時間はtbと長くなり、その時間的変化から沸騰点を検
出する謂ゆる単純な差分形の検出方法である。As shown in FIG. 5, a method for detecting a boiling point of a liquid heating apparatus is to measure the time required for the temperature sensor to rise by a certain temperature ΔT when the temperature of the temperature sensor exceeds a predetermined temperature, and to measure the boiling point. To start. That is, in the same figure, at a temperature much lower than the boiling point, the time t 1 , t 2 ,..., T n required to increase the constant temperature ΔT is short, but as the temperature approaches the boiling point, the required time increases to tb, This is a so-called simple difference type detection method for detecting a boiling point from a temporal change.
本来、このような液体加熱装置に於ける液体温度の上昇
過程は、第６図に示すように、液量によって温度センサ
ーから得られる電圧の上昇率と沸騰点を与える電圧B1,B
2,B3が異なるので、前記差分形の沸騰点検出方法は簡単
な方法ではあるが次のような欠点を有する。Originally, the rising process of the liquid temperature in such a liquid heating apparatus is performed by the following methods: the rising rate of the voltage obtained from the temperature sensor and the voltages B 1 , B
Since B 2 and B 3 are different, the difference type boiling point detection method is a simple method, but has the following disadvantages.
（１）沸騰前の温度上昇率から液量を知り、予め用意さ
れた沸騰後の温度上昇率の表の中から該当するものを選
び、沸騰点の基準値として設定し、沸騰点の検出を行う
ので（特願昭62-124816）、ソフト・ウェアが複雑にな
り且つ一品一様なので汎用性がない。(1) The amount of liquid is known from the temperature rise rate before boiling, and a corresponding one is selected from a table of the temperature rise rate after boiling prepared in advance and set as a reference value of the boiling point, and the detection of the boiling point is performed. Since it is performed (Japanese Patent Application No. 62-124816), the software becomes complicated and uniform, so there is no versatility.
（２）水量が少なく電源電圧が高くなった場合や、対流
や撹拌等により温度リップルが大きい場合は、沸騰点検
出まで標準状態の２倍以上の時間を要する。(2) When the amount of water is small and the power supply voltage is high, or when the temperature ripple is large due to convection or agitation, it takes more than twice as long as the standard state until the boiling point is detected.
（３）水量が多く電源電圧が低くなった場合や、液槽の
保温状態が悪い場合、或いは温度センサーの応答時間が
遅く、感度が低い場合等は、沸騰点以下で沸騰と誤判定
してしまう。このように単純な差分形の沸騰点検出方法
は、経済的にも性能面でも十分とは言えない。(3) When the amount of water is large and the power supply voltage is low, when the heat retention state of the liquid tank is poor, or when the response time of the temperature sensor is slow and the sensitivity is low, the boiling point is erroneously determined to be below the boiling point. I will. Such a simple difference-type boiling point detection method is not economically and sufficiently satisfactory in performance.
（発明が解決しようとする問題点） 本発明は、動作条件によらず汎用性があり、正確な沸
騰点検出を短時間で行う経済的方法を提供することにあ
る。(Problems to be Solved by the Invention) An object of the present invention is to provide an economical method which is versatile regardless of operating conditions and performs accurate boiling point detection in a short time.
（問題点を解決する為の手段） 前記目的を達成するために、本発明による沸騰点検出
方法は、液体加熱装置に於いて、温度センサーから得ら
れる液体の単位温度当りの上昇時間に関する隣接した値
の２乗以上のべき乗の差分値が、最大の変化を示す時点
を沸騰点として検出することを特徴とするものである。(Means for Solving the Problems) In order to achieve the above object, a method for detecting a boiling point according to the present invention relates to a method for detecting a boiling point of a liquid obtained from a temperature sensor in a liquid heating apparatus. It is characterized in that a point in time at which a difference value of a power of two or more of the value shows a maximum change is detected as a boiling point.
（実施例） 以下、図面を参照して本発明を更に詳しく説明する。(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings.
本実施例では液体加熱装置として身近な沸騰型ジャー・
ポットを用いて説明する。In the present embodiment, a familiar boiling jar is used as a liquid heating device.
This will be described using a pot.
第４図に於ける温度センサー３と温度制御器５の構成を
第１図に示す。第１図に於いて、温度センサー３はＢ定
数4330K,R（200℃）＝0.62kΩのサーミスタであり、R1
＝7.26kΩ,Vcc＝5Vである。６はオペアンプによる増幅
器であり、ゲインは３倍とした。７は８ビットA/D変換
器内蔵のマイクロ・コンピューター、８は接点容量10A
のリレーである。又、第４図に於いて、ジャー・ポット
の使用できる容積は0.3〜2.4lのものを使い、ヒーター
は700Wのマイカ・ヒーターである。FIG. 1 shows the configuration of the temperature sensor 3 and the temperature controller 5 in FIG. In Figure 1, the temperature sensor 3 is a thermistor B constant 4330K, R (200 ℃) = 0.62kΩ, R 1
= 7.26 kΩ, Vcc = 5V. Reference numeral 6 denotes an amplifier using an operational amplifier, and the gain is tripled. 7 is a microcomputer with a built-in 8-bit A / D converter, 8 is a contact capacity of 10A
It is a relay. In FIG. 4, the usable volume of the jar pot is 0.3 to 2.4 liters, and the heater is a 700 W mica heater.
まず、水量を0.3lとし加熱をスタートさせ温度変化の様
子をマイクロ・コンピューターにより次のように計算さ
せる。First, the heating was started with the water volume set to 0.3 l, and the state of the temperature change was calculated by the microcomputer as follows.
Δ（ｎ）＝ｔ（ｎ）−ｔ（ｎ−１） （差分） Δ(n)2＝t(n)2−ｔ（ｎ−１）2 （２乗の差分） 但し、ｔ（ｎ）,t（ｎ−１）は各々温度が単位量ΔＴだ
け上昇するのに要する時間であり、本実施例ではΔＴ＝
1degとした。時間の経過から上昇する水温によって変化
する温度センサー３の出力電圧の様子を第２図（ａ）
に，同様に温度上昇に伴って得られる上昇時間の差分値
Δ（ｎ），および２乗の差分値Δ(n)2の沸騰点付近の変
化の様子を第２図（ｂ）に示す。第２図（ｂ）によれば
差分値Δ（ｎ）は沸騰点前から上がり始め、Δ（ｎ）＞
ｅで沸騰点と見倣すわけである。Δ（ｎ）の変化は緩慢
で、真の沸騰点は曖昧であり、Δ（ｎ）が増加し始めて
から検出までの応答時間は約50秒の遅れをもっている。
しかしながら、Δ(n)2は真の沸騰点付近で最大の変化を
示し、Δ(n)2−Δ（ｎ＋１）2＞ｅとなれば容易に沸騰
点を検出できるので、応答時間の遅れは約20秒程度であ
る。又、液量が少ない場合、沸騰前では1deg当りの上昇
時間は短いので、沸騰前に沸騰点を誤検出することはほ
とんどない。ここでｅはΔ（ｎ）の増加を表わすのに十
分な基準値である。次に水量を2.4lとし、前記と同様な
方法で加熱した様子を第３図（ａ）（ｂ）に示す。第３
図（ｂ）によればΔ（ｎ）の沸騰点付近の変化は緩慢で
あり、Δ（ｎ）＞ｅを沸騰点としたとき、対流の影響や
電源変動等の外乱があると沸騰点以前に前記状態となっ
てしまう場合がある。これは第３図（ｂ）のΔ（ｎ）が
沸騰前でも20秒程度の大きな値を示すので、一定のｅで
は沸騰点の誤検出は極めて高い確率となる。これに対
し、Δ(n)2は値も大きく明確に最大の変化を示し、沸騰
点に於いてはΔ(n)2−Δ（ｎ−１）2＞ｅを十分満足す
るので、外乱があっても誤検出の可能性は極めて少なく
なる。尚、本実施例ではA/Dコンバーターの分解能と精
度及び外乱を考慮し、20mV/bitの分解能でｅ＝20秒とし
た。このように単位温度当りの上昇時間の２乗の差分値
は、外乱を除くのに有効な方法であり、対流や撹拌等に
より温度リップルが更に大きい場合は、２乗以上のべき
乗の差分値の変化をとらえることによってその影響を除
去できることは明らかである。尚、べき乗のべき数が整
数でない場合も原理的には可能であるが計算が複雑にな
り実用的ではない。本実施例で示した２乗の差分の計算
は、 ［ｔ（ｎ）＋ｔ（ｎ−１）］×［ｔ（ｎ）−ｔ（ｎ−
１）］ の形に変形でき、カウンター，タイマー機能や加減算と
シフト命令で非常に簡単に実行できるのでソフトウェア
の負担は著しく軽減される。Δ (n) = t (n) −t (n−1) (difference) Δ (n) 2 = t (n) 2 −t (n−1) 2 (square difference) where t (n) , t (n-1) are the time required for the temperature to rise by the unit amount ΔT, and in this embodiment, ΔT =
1 deg. FIG. 2 (a) shows the state of the output voltage of the temperature sensor 3 which changes according to the water temperature rising from the passage of time.
FIG. 2 (b) shows how the difference value Δ (n) of the rise time and the squared difference value Δ (n) 2 similarly obtained with the temperature rise near the boiling point. According to FIG. 2 (b), the difference value Δ (n) starts rising before the boiling point, and Δ (n)>
e is imitated as the boiling point. The change in Δ (n) is slow, the true boiling point is ambiguous, and the response time from when Δ (n) starts increasing until detection is delayed by about 50 seconds.
However, Δ (n) 2 shows the largest change near the true boiling point, and if Δ (n) 2 −Δ (n + 1) 2 > e, the boiling point can be easily detected. It is about 20 seconds. In addition, when the liquid amount is small, the rise time per deg is short before boiling, so that the boiling point is hardly erroneously detected before boiling. Where e is a reference value sufficient to represent an increase in Δ (n). Next, FIGS. 3 (a) and 3 (b) show a state in which the amount of water is set to 2.4 l and heating is performed in the same manner as described above. Third
According to FIG. 6 (b), the change of Δ (n) near the boiling point is slow, and when Δ (n)> e is the boiling point, if there is a disturbance such as the influence of convection or power supply fluctuation, the temperature before the boiling point is obtained. May be in the state described above. This is because Δ (n) in FIG. 3 (b) shows a large value of about 20 seconds even before boiling, so that for a constant e, the erroneous detection of the boiling point has an extremely high probability. On the other hand, the value of Δ (n) 2 is large and clearly shows the largest change, and the boiling point sufficiently satisfies Δ (n) 2 −Δ (n−1) 2 > e. Even so, the possibility of erroneous detection is extremely reduced. In this embodiment, e = 20 seconds at a resolution of 20 mV / bit in consideration of the resolution, accuracy, and disturbance of the A / D converter. As described above, the difference value of the square of the rise time per unit temperature is an effective method for eliminating disturbance. When the temperature ripple is further increased due to convection, agitation, or the like, the difference value of the squared or higher power difference value is obtained. Obviously, capturing the change can eliminate that effect. It should be noted that it is possible in principle if the power of the power is not an integer, but the calculation becomes complicated and impractical. The calculation of the squared difference shown in this embodiment is [t (n) + t (n−1)] × [t (n) −t (n−
1)], and can be executed very easily with the counter and timer functions and addition / subtraction and shift instructions, so that the load on software is significantly reduced.
又、対象とする液体は水のみならず液体一般について適
用できることも明らかである。It is also apparent that the target liquid can be applied not only to water but also to liquids in general.
（発明の効果） 以上説明したように、本発明によれば、温度センサー
から得られる液体の単位温度当りの上昇時間に関する隣
接した値の２乗以上のべき乗の差分値が、最大の変化を
示す時点を沸騰点として検出することにより、 （１）液量によらず加減算とシフト命令のみの簡単なソ
フト・ウェアで汎用性の高い沸騰点検出ができる。(Effects of the Invention) As described above, according to the present invention, the difference between the powers of two or more adjacent values of the rise time per unit temperature of the liquid obtained from the temperature sensor indicates the largest change. By detecting the point in time as a boiling point, (1) a highly versatile boiling point can be detected with simple software including only addition / subtraction and a shift command regardless of the liquid amount.
（２）動作状態に寄らず正確で早い沸騰点検出が可能と
なる。(2) It is possible to accurately and quickly detect a boiling point regardless of an operation state.
（３）外乱による誤検出を極めて少なくすることができ
る等の利点を得ることができる。(3) Advantages such as erroneous detection due to disturbance can be extremely reduced.
第１図は本発明の一実施例を示す要部回路構成図。第２
図は水量0.3lの場合におけるグラフで、（ａ）は上昇す
る水温によって変化する温度センサーの出力電圧，
（ｂ）は温度上昇に伴う差分値Δ（ｎ），および２乗の
差分値Δ(n)2の沸騰点付近の変化を表したもの。第３図
は水量2.4lの場合におけるグラフで、（ａ）は上昇する
水温によって変化する温度センサーの出力電圧，（ｂ）
は温度上昇に伴う差分値Δ（ｎ），および２乗の差分値
Δ(n)2の沸騰点付近の変化を表したもの。第４図は液体
加熱装置の沸騰点検出方法説明図、第５図は従来の沸騰
点検出方法における検出温度と時間との関係を示すグラ
フ、第６図は従来の沸騰点検出方法における検出温度と
出力電圧の関係を示すグラフである。 １……液槽、２……液体 ３……温度センサー、４……ヒーター ５……温度制御器、６……増幅器 ７……マイクロ・コンピューター ８……リレーFIG. 1 is a main part circuit configuration diagram showing one embodiment of the present invention. Second
The figure is a graph when the water volume is 0.3 l. (A) is the output voltage of the temperature sensor that changes with rising water temperature,
(B) shows the change of the difference value Δ (n) 2 and the squared difference value Δ (n) 2 near the boiling point as the temperature rises. FIG. 3 is a graph in the case of a water volume of 2.4 liters, where (a) is the output voltage of the temperature sensor that changes with rising water temperature, (b)
Represents changes near the boiling point of the difference value Δ (n) and the squared difference value Δ (n) 2 accompanying the temperature rise. FIG. 4 is an explanatory diagram of a boiling point detecting method of the liquid heating device, FIG. 5 is a graph showing a relationship between a detected temperature and time in a conventional boiling point detecting method, and FIG. 6 is a detected temperature in a conventional boiling point detecting method. 6 is a graph showing a relationship between the output voltage and the output voltage. 1 ... liquid tank 2 ... liquid 3 ... temperature sensor 4 ... heater 5 ... temperature controller 6 ... amplifier 7 ... microcomputer 8 ... relay
Claims (1)
得られる液体の単位温度当りの上昇時間に関する隣接し
た値の２乗以上のべき乗の差分値が、最大の変化を示す
時点を沸騰点として検出することを特徴とする沸騰点検
出方法。In a liquid heating apparatus, a point at which a difference value of a power of two or more of adjacent values related to a rise time per unit temperature of a liquid obtained from a temperature sensor shows a maximum change is defined as a boiling point. A method for detecting a boiling point, comprising: detecting a boiling point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63108825A JP2714812B2 (en) | 1988-04-30 | 1988-04-30 | Boiling point detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63108825A JP2714812B2 (en) | 1988-04-30 | 1988-04-30 | Boiling point detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01280244A JPH01280244A (en) | 1989-11-10 |
| JP2714812B2 true JP2714812B2 (en) | 1998-02-16 |
Family
ID=14494489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63108825A Expired - Lifetime JP2714812B2 (en) | 1988-04-30 | 1988-04-30 | Boiling point detection method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2714812B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5380091A (en) * | 1989-04-08 | 1995-01-10 | Alba Tools Limited | Indicating device |
| GB9409296D0 (en) * | 1994-05-10 | 1994-06-29 | Alba Tools Ltd | Brake fluid analyser |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5956631A (en) * | 1982-09-25 | 1984-04-02 | Matsushita Electric Ind Co Ltd | Boiling detection device |
| JPS6041915A (en) * | 1983-08-19 | 1985-03-05 | 松下電器産業株式会社 | Heating machinery |
-
1988
- 1988-04-30 JP JP63108825A patent/JP2714812B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01280244A (en) | 1989-11-10 |
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