JPH0565817B2 - - Google Patents
Info
- Publication number
- JPH0565817B2 JPH0565817B2 JP7708084A JP7708084A JPH0565817B2 JP H0565817 B2 JPH0565817 B2 JP H0565817B2 JP 7708084 A JP7708084 A JP 7708084A JP 7708084 A JP7708084 A JP 7708084A JP H0565817 B2 JPH0565817 B2 JP H0565817B2
- Authority
- JP
- Japan
- Prior art keywords
- heating
- sample
- temperature
- drying
- weight
- 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
Links
- 238000010438 heat treatment Methods 0.000 claims description 44
- 238000001035 drying Methods 0.000 claims description 15
- 238000005303 weighing Methods 0.000 claims description 9
- 230000000694 effects Effects 0.000 description 4
- 230000006870 function Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
- G01N5/045—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder for determining moisture content
Description
【発明の詳細な説明】
(イ) 産業上の利用分野
本発明は、粉体、繊維、紙等の試料に含まれる
付着水分を、試料の加熱乾燥時の重量減少量によ
つて測定する、乾燥減量方式の水分計に関する。[Detailed Description of the Invention] (a) Industrial Application Field The present invention measures the amount of attached moisture contained in a sample such as powder, fiber, paper, etc. by the amount of weight loss during heating and drying of the sample. Concerning a moisture meter using a loss on drying method.
(ロ) 従来技術
一般に、乾燥減量方式の水分計においては、加
熱前の試料重量と加熱乾燥後の試料重量を天びん
で測定することにより、試料の水分率が算出され
る。また、通常、試料の乾燥が完了したか否かを
判定する為に、試料は天びんの皿上に載せられた
状態で加熱される。ところが、加熱することによ
つて、皿周辺の温度上昇により対流が発生し、乾
燥完了時にはこの対流によつて皿に浮力が作用し
ており、天びんの秤量値には誤差が包含されてい
る。この誤差の大きさは通常、加熱温度によつて
変化する。(B) Prior Art Generally, in a moisture meter using the loss on drying method, the moisture content of a sample is calculated by measuring the weight of the sample before heating and the weight of the sample after drying by heating using a balance. Further, in order to determine whether or not the sample has been completely dried, the sample is usually heated while being placed on a balance pan. However, due to heating, convection is generated due to the rise in temperature around the dish, and when drying is complete, this convection exerts buoyancy on the dish, and the weighing value of the balance includes an error. The magnitude of this error usually changes depending on the heating temperature.
従来のこの種の水分計においては、この誤差を
無視して水分率が算出されていたから、その測定
値は自と正確ではない。水分率の小さい試料等、
誤差を無視し得ない試料については、加熱温度ご
とにブランクテストを行い、測定値に対して補正
計算を行う必要があつた。 In conventional moisture meters of this type, the moisture content was calculated ignoring this error, so the measured values were not accurate. Samples with low moisture content, etc.
For samples where the error could not be ignored, it was necessary to conduct a blank test at each heating temperature and perform correction calculations on the measured values.
(ハ) 目的
本発明の目的は、上述した対流に基づく秤量誤
差を自動的に補正して、常に正確な水分率を測定
することのできる水分計を提供することにある。(C) Purpose An object of the present invention is to provide a moisture meter that can automatically correct the weighing error caused by the above-mentioned convection and can always accurately measure moisture content.
(ニ) 構成
本発明の特徴とするところは、天びんの皿を収
容する加熱室内の所定位置に温度センサを配設
し、加熱時に加熱室内に発生する対流によつて皿
に作用する浮力に基づく天びんの秤量誤差の経時
変化と加熱温度との関係を、あらかじめ測定して
メモリに記憶しておき、温度センサの出力とその
メモリの内容とから、加熱乾燥時の試料重量検出
値を補正演算して水分率を算出するように構成し
たことにある。(D) Structure The feature of the present invention is that a temperature sensor is disposed at a predetermined position in the heating chamber that houses the pan of the balance, and the temperature sensor is based on the buoyancy force that acts on the pan due to the convection generated in the heating chamber during heating. The relationship between the change in weighing error of the balance over time and the heating temperature is measured in advance and stored in memory, and the detected value of the sample weight during heating and drying is corrected and calculated from the output of the temperature sensor and the contents of the memory. The reason is that the system is configured to calculate the moisture content based on the
(ホ) 実施例
本発明の実施例を、上下、図面に基づいて説明
する。(E) Embodiments Examples of the present invention will be described based on the upper and lower drawings.
第１図は本発明実施例の構成図である。 FIG. 1 is a block diagram of an embodiment of the present invention.
電子天びん１は試料皿２に作用する荷重を検出
し、その検出値を重量検出部１ａから電気信号で
出力する。その出力はＡ−Ｄ変換器３を介して演
算制御部４に取り込まれる。 The electronic balance 1 detects the load acting on the sample plate 2, and outputs the detected value as an electric signal from the weight detection section 1a. The output is taken into the arithmetic control section 4 via the A-D converter 3.
試料皿２は風防５によつてその周りを囲まれて
おり、その上方には試料を加熱乾燥する為のヒー
タ６が配設されている。ヒータ６の周りはヒータ
カバー７で囲まれており、このヒータカバー７と
風防５によつて加熱室を形成している。ヒータ６
に近接して温度センサ８が配設されており、その
出力は温度検出器９に入力され、温度に比例した
電気信号として出力される。温度検出器９の出力
はＡ−Ｄ変換器１０を介して演算制御部４に取り
込まれるとともに、ヒータ６に電源を供給するヒ
ータ制御部１１に供給され、ヒータ６による加熱
温度の制御に供される。 The sample dish 2 is surrounded by a windshield 5, and a heater 6 for heating and drying the sample is provided above the windshield 5. The heater 6 is surrounded by a heater cover 7, and the heater cover 7 and the windshield 5 form a heating chamber. Heater 6
A temperature sensor 8 is disposed adjacent to the temperature sensor 8, and its output is input to a temperature detector 9, which outputs it as an electrical signal proportional to the temperature. The output of the temperature detector 9 is taken into the arithmetic control section 4 via the A-D converter 10, and is also supplied to the heater control section 11 that supplies power to the heater 6, and is used to control the heating temperature by the heater 6. Ru.
演算制御部４はマイクロコンピユータで構成さ
れ、測定プログラムや各種演算の実行、および各
周辺装置の制御を行うCPU４１、後述する加熱
温度と電子天びん１の秤量誤差の関係や測定プロ
グラム等が書き込まれたROM４２、各種演算結
果や重量検出値、温度検出値等を記憶するエリア
を備えたRAM４３、および外部機器からの信号
を入力する為の入力ポート４４を備えており、こ
れらは互いにバスラインで接続されている。入力
ポート４４には上述したＡ−Ｄ変換器３および１
０の出力の他に、加熱開始から乾燥完了までの時
間を計測するタイマ１２の出力が入力される。演
算制御部４には、また、CPU４１の指令によつ
て算出された水分率の表示を行う表示器１３、お
よびCPU４１に指示を与える為のキーボード１
４が接続されている。 The arithmetic control unit 4 is composed of a microcomputer, in which a CPU 41 that executes measurement programs and various arithmetic operations and controls each peripheral device, a relationship between heating temperature and weighing error of the electronic balance 1, and a measurement program, etc., which will be described later, are written. It is equipped with a ROM 42, a RAM 43 with an area for storing various calculation results, detected weight values, detected temperature values, etc., and an input port 44 for inputting signals from external devices, and these are connected to each other by a bus line. ing. The above-mentioned A-D converters 3 and 1 are connected to the input port 44.
In addition to the output of 0, the output of a timer 12 that measures the time from the start of heating to the completion of drying is input. The arithmetic control unit 4 also includes a display 13 for displaying the moisture content calculated according to commands from the CPU 41, and a keyboard 1 for giving instructions to the CPU 41.
4 is connected.
次に作用を述べる。試料Ｓを試料皿２上に載
せ、キーボード１４から測定開始の指令を与える
と、タイマ１２が計時を開始するとともに、測定
当初の試料重量W1が読み取られ、RAM４３内に
格納される。次に、ヒータ６が駆動されて、所定
の設定温度によつて試料Ｓの加熱を開始する。試
料Ｓの加熱乾燥が完了すると、試料重量は変化し
なくなるから、これを検知してタイマ１２をスト
ツプし、このときの試料重量W2と温度センサ８
によつて検出された温度ＴとをRAM４３内に格
納する。水分率Ｍは、加熱前後の試料重量W1と
W2、およびW2検出時の温度Ｔによつて、次の式
で算出され、表示器１３に表示される。 Next, we will discuss the effect. When the sample S is placed on the sample plate 2 and a command to start measurement is given from the keyboard 14, the timer 12 starts counting, and the sample weight W1 at the beginning of the measurement is read and stored in the RAM 43. Next, the heater 6 is driven to start heating the sample S at a predetermined set temperature. Once heating and drying of the sample S is completed, the sample weight will not change, so this is detected and the timer 12 is stopped, and the sample weight W2 and the temperature sensor 8 at this time are detected.
The detected temperature T is stored in the RAM 43. The moisture content M is the sample weight W 1 before and after heating.
It is calculated by the following formula using W 2 and the temperature T at the time of W 2 detection, and is displayed on the display 13.
Ｍ＝W1−W2＋ｆ(T)／W1
式において、ｆ(T)は温度Ｔの関数で、温度Ｔに
おける加熱室内の対流の発生による電子天びんの
ゼロ点変化量である。この温度Ｔとｆ(T)との関係
は、実験的にあらかじめ求められており、ROM
４２内に関数式又は関数表として記憶されてお
り、以下にこの関係を説明する。 M=W 1 −W 2 +f(T)/W In the formula , f(T) is a function of temperature T, and is the amount of change in the zero point of the electronic balance due to the occurrence of convection in the heating chamber at temperature T. This relationship between temperature T and f(T) has been experimentally determined in advance, and the ROM
42 as a function formula or function table, and this relationship will be explained below.
第２図に加熱温度（T1，T2，T3）をパラメー
タとした加熱時間ｔと対流によるゼロ点変化量Ｗ
との一般的な関係を示す。Ｗは第１図の矢印で示
すような上昇気流による試料皿２の持ち上げ効果
により、マイナスの値を採る。また、Ｗの値は試
料皿２の形状や加熱室内の形状、構造が決まれ
ば、実験的に第２図に示す如く加熱温度と加熱時
間の関数として求めることができる。そこで、
ROM４２内に、第２図に示すような、加熱温度
Ｔおよび加熱開始後の経過時間ｔと、対流による
秤量誤差Ｗとの関係を予め測定して記憶してお
き、温度センサ８の出力とタイマ１２の出力から
秤量誤差Ｗ（＝ｆ(T)を読み出し、前述した式によ
つて水分率Ｍを求めると、得られた水分率Ｍから
対流による影響は除去される。 Figure 2 shows the heating time t and the amount of zero point change W due to convection using the heating temperature (T 1 , T 2 , T 3 ) as a parameter.
shows the general relationship between W takes a negative value due to the lifting effect of the sample plate 2 due to the upward airflow as shown by the arrow in FIG. Further, the value of W can be determined experimentally as a function of heating temperature and heating time, as shown in FIG. 2, once the shape of the sample dish 2 and the shape and structure of the heating chamber are determined. Therefore,
In the ROM 42, as shown in FIG. 2, the relationship between the heating temperature T, the elapsed time t after the start of heating, and the weighing error W due to convection is measured and stored in advance, and the output of the temperature sensor 8 and the timer are When the weighing error W (=f(T)) is read out from the output of No. 12 and the moisture content M is determined using the above-mentioned formula, the influence of convection is removed from the moisture content M obtained.
ところで、この第２図に示す如く、ある時間tc
が経過した後には、気流は定常状態となる関係
上、Ｗは一定の値を採る。すなわち、時間tcが経
過した後には、温度(T)と対流によるゼロ点変化量
（−Ｗ）との関係は第３図に示す通りとなる。 By the way, as shown in Figure 2, at a certain time tc
After , W takes a constant value because the airflow is in a steady state. That is, after the time tc has elapsed, the relationship between the temperature (T) and the amount of change in the zero point (-W) due to convection is as shown in FIG.
このことから、加熱開始後の経過時間がtc以上
経過した後の定常状態においては、第３図のよう
に加熱温度Ｔと対流による秤量誤差Ｗとの関係の
みを記憶しておき、乾燥終了時点におけるタイマ
による計時結果がtc以上であれば、この温度セン
サ８の出力Ｔから直ちにＷを読み出して補正演算
に供しても、全く同様の作用効果が得られる。 Therefore, in a steady state after the elapsed time from the start of heating to tc or more, only the relationship between the heating temperature T and the weighing error W due to convection is memorized as shown in Fig. 3, and at the end of drying If the time measurement result by the timer in is equal to or greater than tc, even if W is immediately read from the output T of this temperature sensor 8 and subjected to correction calculation, exactly the same effect can be obtained.
以上の実施例では、温度センサ８をヒータ６に
近接して配設し、実質的にヒータ６の温度によつ
てゼロ点変化量を求めたが、これはヒータ６と試
料皿２の距離が固定されている場合にのみ有効で
ある。この距離が可変なるよう構成されている場
合や、熱源が赤外線ランプのように温度制御が困
難な場合においては、温度センサ８をより試料皿
２に近付けて配設することが好ましい。 In the above embodiment, the temperature sensor 8 was disposed close to the heater 6, and the amount of change in the zero point was determined based on the temperature of the heater 6, but this is because the distance between the heater 6 and the sample plate 2 is Valid only if fixed. When this distance is configured to be variable, or when the heat source is difficult to control temperature such as an infrared lamp, it is preferable to arrange the temperature sensor 8 closer to the sample plate 2.
(ヘ) 効果
以上説明したように、本発明によれば、加熱室
内の所定位置に温度センサを配置するとともに、
加熱開始後からの経過時間を計測する計時手段
と、加熱温度と加熱で発生する対流に基づく天び
んの秤量誤差の経時変化との関係を記憶するメモ
リを設け、そのメモリの内容と温度センサおよび
計時手段の出力とから、乾燥時における試料重量
検出値を補正する演算部を備えているので、加熱
開始後の任意の時間に乾燥が完了しても、自動的
に常に正確に浮力による誤差分を補正して水分率
を算出することができ、従来装置のようにブラン
クテストや繁雑な補正計算を行うまでもなく、常
に正確な水分率を測定することができる。(f) Effects As explained above, according to the present invention, the temperature sensor is disposed at a predetermined position in the heating chamber, and
A timer is provided to measure the elapsed time from the start of heating, and a memory is provided to store the relationship between the heating temperature and the change in weighing error of the balance over time due to convection generated by heating. Since it is equipped with a calculation unit that corrects the detected value of sample weight during drying based on the output of the means, even if drying is completed at any time after the start of heating, the error due to buoyancy is automatically and always accurately corrected. The moisture content can be calculated by correcting it, and the moisture content can always be accurately measured without the need for blank tests or complicated correction calculations as in conventional devices.
第１図は本発明実施例の構成図、第２図は加熱
温度をパラメータとして加熱時間とゼロ点変化量
の関係を示すグラフ、第３図は加熱温度とゼロ点
変化量の関係を示すグラフである。
１……電子天びん、２……試料皿、４……演算
制御部、５……風防、６……ヒータ、７……ヒー
タカバー、８……温度センサ、９……温度検出
器、１１……ヒータ制御部、１２……タイマ、１
３……表示器。
Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is a graph showing the relationship between heating time and zero point change amount using heating temperature as a parameter, and Fig. 3 is a graph showing the relationship between heating temperature and zero point change amount. It is. DESCRIPTION OF SYMBOLS 1...Electronic balance, 2...Sample plate, 4...Arithmetic control unit, 5...Windshield, 6...Heater, 7...Heater cover, 8...Temperature sensor, 9...Temperature detector, 11... ...Heater control unit, 12...Timer, 1
3...Indicator.
Claims (1)
力する天びんと、上記試料皿を内部に収容する加
熱室内に配設され、試料を加熱して乾燥させる為
の熱源を有し、加熱前の試料重量と加熱乾燥後の
試料重量とから、試料の水分率を求め得るよう構
成された装置において、上記加熱室内に所定位置
に配設された温度センサと、加熱開始後からの経
過時間を計測する計時手段と、加熱温度と加熱で
発生する対流に基づく上記天びんの秤量誤差の経
時変化との関係を記憶するメモリと、上記温度セ
ンサおよび計時手段の出力と上記メモリの内容と
から、乾燥時における試料重量検出値を補正する
演算部を備えたことを特徴とする電子式水分計。1 A balance that detects the weight of the sample on the sample plate and outputs an electrical signal, and a heating chamber that houses the sample plate and has a heat source for heating and drying the sample. In an apparatus configured to determine the moisture content of a sample from the sample weight and the sample weight after heating and drying, a temperature sensor installed at a predetermined position in the heating chamber and a time elapsed from the start of heating are used. A timer to be measured, a memory that stores the relationship between the heating temperature and the change in weighing error of the balance over time based on convection generated by heating, and the output of the temperature sensor and the timer and the contents of the memory, the drying An electronic moisture meter characterized by being equipped with a calculation unit that corrects a sample weight detected value at a time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7708084A JPS60219545A (en) | 1984-04-16 | 1984-04-16 | Electronic moisture meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7708084A JPS60219545A (en) | 1984-04-16 | 1984-04-16 | Electronic moisture meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60219545A JPS60219545A (en) | 1985-11-02 |
| JPH0565817B2 true JPH0565817B2 (en) | 1993-09-20 |
Family
ID=13623796
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7708084A Granted JPS60219545A (en) | 1984-04-16 | 1984-04-16 | Electronic moisture meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60219545A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003509679A (en) * | 1999-09-17 | 2003-03-11 | シーイーエム・コーポレーション | How to correct weighing errors during microwave heating |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01282464A (en) * | 1988-05-10 | 1989-11-14 | Chubu Electric Power Co Inc | Moisture measuring device |
| JP2912820B2 (en) * | 1994-03-29 | 1999-06-28 | 関西電力株式会社 | Industrial analysis methods |
| JPH11326172A (en) * | 1998-05-19 | 1999-11-26 | Yanagawa Giken:Kk | Water meter |
| US6566637B1 (en) | 2000-06-28 | 2003-05-20 | Cem Corporation | Microwave assisted content analyzer |
| KR100556503B1 (en) * | 2002-11-26 | 2006-03-03 | 엘지전자 주식회사 | Control Method of Drying Time for Dryer |
| EP1850110A1 (en) * | 2006-04-25 | 2007-10-31 | Mettler-Toledo AG | Measuring device for gravimetric moisture determination |
-
1984
- 1984-04-16 JP JP7708084A patent/JPS60219545A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003509679A (en) * | 1999-09-17 | 2003-03-11 | シーイーエム・コーポレーション | How to correct weighing errors during microwave heating |
| JP4908707B2 (en) * | 1999-09-17 | 2012-04-04 | シーイーエム・コーポレーション | How to correct gravimetric error during microwave heating |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60219545A (en) | 1985-11-02 |
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