JPH0242416B2 - - Google Patents
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- Publication number
- JPH0242416B2 JPH0242416B2 JP58199919A JP19991983A JPH0242416B2 JP H0242416 B2 JPH0242416 B2 JP H0242416B2 JP 58199919 A JP58199919 A JP 58199919A JP 19991983 A JP19991983 A JP 19991983A JP H0242416 B2 JPH0242416 B2 JP H0242416B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- phase
- feedback
- output voltage
- feedback amplifier
- 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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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Electromagnetism (AREA)
- Power Engineering (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
- Continuous Casting (AREA)
Description
【発明の詳細な説明】
この発明は、渦流式湯面レベル測定法に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vortex-type hot water level measurement method.
例えば、鋼を連続鋳造する場合、鋳片の品質を
向上させるためにモールド内の溶鋼面レベルを一
定に維持する必要があり、このためには前記溶鋼
面レベルを正確に計測する必要がある。 For example, when continuously casting steel, it is necessary to maintain a constant level of the molten steel in the mold in order to improve the quality of the slab, and for this purpose it is necessary to accurately measure the level of the molten steel.
従来、モールド内の溶鋼面レベルを計測する方
法として、モールドの上下方向に複数本の熱電対
を取り付け、熱電対による測定結果に基づいて溶
鋼面レベルを計測する熱電対法があつた。 Conventionally, as a method for measuring the molten steel surface level in a mold, there has been a thermocouple method in which multiple thermocouples are attached in the vertical direction of the mold and the molten steel surface level is measured based on the measurement results by the thermocouples.
また、別の方法としてRI線源をモールドの一
方壁に取り付け、モールドの他方壁にRI線の強
度を測定するセンサーを設置し、センサーによつ
て測定されたRI線の強度変化からモールド内の
溶鋼面レベルを計測するRI法等があつた。 Another method is to attach an RI source to one wall of the mold, and install a sensor to measure the intensity of the RI rays on the other wall of the mold. The RI method was introduced to measure the level of molten steel.
しかし、上述した熱電対法は、モールド壁に熱
電対を設置するための加工を施こす必要があり、
しかも、モールド壁を介して溶鋼面レベルを計測
するので応答性が悪い。 However, the thermocouple method described above requires processing to install the thermocouple on the mold wall.
Moreover, since the molten steel surface level is measured through the mold wall, responsiveness is poor.
一方、上述したRI法は、熱電対法と同様にモ
ールド壁を介して溶鋼面レベルを計測するので応
答性が悪く、しかも、RI線が人体に悪影響を及
ぼすので安全管理上問題があつた。 On the other hand, the above-mentioned RI method, like the thermocouple method, has poor responsiveness because it measures the molten steel surface level through the mold wall, and also has safety management problems because the RI rays have a negative effect on the human body.
そこで、本願発明者等は、上述した問題点を解
決するための渦流式湯面レベル測定法を先に提案
した。 Therefore, the inventors of the present application first proposed a vortex-type hot water level measurement method to solve the above-mentioned problems.
この渦流式湯面レベル測定法を第１図を参照し
ながら説明する。第１図において、モールド１内
にはタンデイツシユ（図示せず）から溶鋼２が連
続的に注入される。溶鋼２面上に検出ヘツド３が
垂直に固定されている。検出ヘツド３は、１個の
１次コイル４と、１次コイル４の上下に設けられ
た１対の２次コイル５ａおよび５ｂを有する。発
振器６は一定周波数の交流電圧eiを帰還増幅器７
を介して１次コイル４に加える。差動増幅器８は
１対の２次コイル５ａおよび５ｂに誘起される電
圧の差をとる。加算器９は帰還増幅器７の出力電
圧epと差動増幅器８の出力電圧とを加算する。こ
の加算された出力電圧、即ち、帰還電圧eadは帰
還増幅器７に帰還される。 This vortex type hot water level measuring method will be explained with reference to FIG. In FIG. 1, molten steel 2 is continuously injected into a mold 1 from a tundish (not shown). A detection head 3 is vertically fixed on the surface of the molten steel 2. The detection head 3 has one primary coil 4 and a pair of secondary coils 5a and 5b provided above and below the primary coil 4. The oscillator 6 feeds back the constant frequency AC voltage e i to the feedback amplifier 7.
It is added to the primary coil 4 via. Differential amplifier 8 takes the difference between the voltages induced in the pair of secondary coils 5a and 5b. Adder 9 adds the output voltage e p of feedback amplifier 7 and the output voltage of differential amplifier 8. This added output voltage, ie, the feedback voltage e ad , is fed back to the feedback amplifier 7.
帰還増幅器７を介して発振器６から一定周波数
の交流電圧eiが１次コイル４に加えられると、磁
束が発生する結果、１対の２次コイル５ａおよび
５ｂに誘起電圧が生じる。一方、前記磁束はモー
ルド１内の溶鋼２と交差して、溶鋼表面に渦電流
が発生する。この反作用として１対の２次コイル
５ａおよび５ｂに生じる誘起電圧が変化するが、
１対の２次コイル５ａおよび５ｂのうち溶鋼２面
に近い２次コイル５ｂの方が溶鋼２面から離れて
いる２次コイル５ａに比べて、より大きく変化す
る。１対の２次コイル５ａおよび５ｂに誘起され
る電圧の差（Vs＝Va−Vb）は検出ヘツド３と
溶鋼２面との間の距離ｌの関数ｆ（ｌ）となる。 When an alternating current voltage e i of a constant frequency is applied to the primary coil 4 from the oscillator 6 via the feedback amplifier 7, magnetic flux is generated, and as a result, an induced voltage is generated in the pair of secondary coils 5a and 5b. On the other hand, the magnetic flux intersects with the molten steel 2 in the mold 1, and eddy currents are generated on the surface of the molten steel. As a reaction to this, the induced voltage generated in the pair of secondary coils 5a and 5b changes,
Of the pair of secondary coils 5a and 5b, the secondary coil 5b closer to the molten steel 2 surface changes more than the secondary coil 5a farther from the molten steel 2 surface. The difference in voltage (Vs=Va-Vb) induced in the pair of secondary coils 5a and 5b is a function f(l) of the distance l between the detection head 3 and the surface of the molten steel 2.
差動増幅器８は１対の２次コイル５ａおよび５
ｂに誘起された電圧の差Vsを演算する。加算器
９は前記差電圧Vsと帰還増幅器７の出力電圧e0
とを加算する。この加算された出力電圧は、帰還
増幅器７に帰還電圧eadとして帰還される。 The differential amplifier 8 includes a pair of secondary coils 5a and 5.
Calculate the voltage difference Vs induced in b. The adder 9 outputs the difference voltage Vs and the output voltage e 0 of the feedback amplifier 7.
Add. This added output voltage is fed back to the feedback amplifier 7 as a feedback voltage e ad .
帰還増幅器７の出力電圧e0は、次式で表わされ
る。 The output voltage e 0 of the feedback amplifier 7 is expressed by the following equation.
e0＝−eiA1／｛１−A1（Ｋ＋A2f（ｌ）｝ …(1)
但し、
ei：発振器６の出力電圧、
A1：帰還増幅器７の増幅度、
A2：差動増幅器８の増幅度、
ｆ（ｌ）：検出ヘツド３と溶鋼２面との間の距離に
よる関数、
Ｋ：定数。e 0 =-e i A 1 / {1-A 1 (K+A 2 f(l)}...(1) where, e i : output voltage of oscillator 6, A 1 : amplification degree of feedback amplifier 7, A 2 : Amplification degree of the differential amplifier 8, f(l): function depending on the distance between the detection head 3 and the molten steel 2 surface, K: constant.
(1)式から明らかなように、帰還増幅器７の出力
電圧e0は、溶鋼２面のレベルに応じて変化するの
で、前記出力電圧e0を測定すればモールド１内の
溶鋼２面のレベルを計測することができる。 As is clear from equation (1), the output voltage e 0 of the feedback amplifier 7 changes depending on the level of the two molten steel surfaces. can be measured.
上述した従来の渦流式湯面レベル測定法は、前
述した何れの方法より優れているが、次のような
問題点があつた。 The conventional vortex level measurement method described above is superior to any of the methods described above, but it has the following problems.
正帰還回路網内に位相偏移が生じると動作が不
安定となつたり、自己発振を起して正確な計測が
行えない。帰還回路網内に生じる位相偏移の原因
としては、次のようなものがある。即ち、
帰還回路を構成する演算器自体の位相遅れ、
帰還回路用配線の分布容量による位相遅れ、
検出ヘツド３と湯面計本体とを結線する同軸
ケーブルの分布容量による影響、
検出ヘツド３とモールド側壁との距離が接近
した場合のモールド壁による影響。 If a phase shift occurs in the positive feedback network, the operation becomes unstable or self-oscillation occurs, making it impossible to perform accurate measurements. The causes of phase shifts within the feedback network include: In other words, the phase delay of the arithmetic unit itself that makes up the feedback circuit, the phase delay due to the distributed capacitance of the feedback circuit wiring, the influence of the distributed capacitance of the coaxial cable connecting the detection head 3 and the water level gauge body, and the influence of the detection head 3 and the mold. Effect of mold wall when the distance from side wall is close.
第２図に帰還回路網内に位相偏移があるときと
ないときの帰還増幅器の出力電圧の特性を示す。 FIG. 2 shows the characteristics of the output voltage of the feedback amplifier with and without phase shift in the feedback network.
第２図に示されるように、位相偏移が存在する
と、出力電圧e0に誤差が生じるとともに、出力電
圧e0がある値以上になると自己発振を起して計測
不能となる。 As shown in FIG. 2, when a phase shift exists, an error occurs in the output voltage e 0 , and when the output voltage e 0 exceeds a certain value, self-oscillation occurs and measurement becomes impossible.
この発明は、上述した問題点を解決するために
なされたものであつて、
１次コイルと１対の２次コイルとから構成され
た検出ヘツドの前記１次コイルに帰還増幅器から
交流電圧を加え、これによつて前記１対の２次コ
イルに生じた誘起電圧の各々の差を差動増幅器に
よつて演算し、前記差電圧と前記帰還増幅器の出
力電圧とを加算器によつて加算し、前記加算電圧
を前記帰還増幅器に帰還することからなる渦流式
湯面レベル測定法において、
前記帰還増幅器に帰還する帰還電圧の位相を、
移相器によつて前記帰還増幅器の出力電圧の位相
と一致させることに特徴を有する。 This invention was made to solve the above-mentioned problems, and includes applying an alternating current voltage from a feedback amplifier to the primary coil of a detection head that is composed of a primary coil and a pair of secondary coils. The difference between the induced voltages thus generated in the pair of secondary coils is calculated by a differential amplifier, and the difference voltage and the output voltage of the feedback amplifier are added by an adder. , in an eddy current hot water level measurement method comprising feeding back the added voltage to the feedback amplifier, the phase of the feedback voltage fed back to the feedback amplifier is
The present invention is characterized in that a phase shifter is used to match the phase of the output voltage of the feedback amplifier.
この発明の一実施態様を図面を参照しながら説
明する。 One embodiment of this invention will be described with reference to the drawings.
第３図は、この発明の一実施態様の概略構成図
である。 FIG. 3 is a schematic diagram of an embodiment of the present invention.
第３図において、発振器６は一定周波数の交流
電圧を帰還増幅器７を介して検出ヘツドの１次コ
イル（図示せず）に加える。差動増幅器８は前記
検出ヘツドに巻れた１対の２次コイル（図示せ
ず）からの誘起電圧の差を演算する。加算器９は
帰還増幅器７の出力電圧e0と差動増幅器８の出力
電圧とを加算する。加算器９は抵抗R1、抵抗R2
および抵抗RNを有する。移相器１０は加算器９
からの帰還電圧eadの位相偏移を補償する。移相
器１０は負帰還抵抗R3，R4、可変抵抗R5および
コンデンサＣを有する。 In FIG. 3, an oscillator 6 applies an alternating voltage of constant frequency via a feedback amplifier 7 to a primary coil (not shown) of the detection head. A differential amplifier 8 calculates the difference in induced voltages from a pair of secondary coils (not shown) wound around the detection head. Adder 9 adds the output voltage e 0 of feedback amplifier 7 and the output voltage of differential amplifier 8. Adder 9 has a resistor R 1 and a resistor R 2
and has a resistance RN . Phase shifter 10 is adder 9
Compensate for the phase shift of the feedback voltage e ad from . Phase shifter 10 has negative feedback resistors R 3 , R 4 , variable resistor R 5 and capacitor C.
加算器９の出力電圧、即ち、差動増幅器８の出
力電圧と帰還増幅器７からの出力電圧e0とを加算
した帰還電圧eadは、次式で表わされる。 The output voltage of the adder 9, that is, the feedback voltage e ad obtained by adding the output voltage of the differential amplifier 8 and the output voltage e 0 from the feedback amplifier 7 is expressed by the following equation.
ead＝RN／R1e0＋RN／R2A2f（ｌ） …(2)
但し、
e0：帰還増幅器７の出力電圧、
A2：差動増幅器８の増幅度、
ｆ（ｌ）：検出ヘツド３と溶鋼２面との間の距離に
よる関数。 e ad = R N /R 1 e 0 + R N /R 2 A 2 f(l) ...(2) However, e 0 : Output voltage of feedback amplifier 7, A 2 : Amplification degree of differential amplifier 8, f( l): A function depending on the distance between the detection head 3 and the molten steel surface 2.
加算器９からの帰還電圧eadは移相器１０に加
えられる。移相器１０は前記帰還電圧eadの位相
偏移を補償して、帰還増幅器７の出力電圧e0の位
相と一致した帰還電圧epを帰還増幅器７に帰還す
る。 A feedback voltage e ad from adder 9 is applied to phase shifter 10 . The phase shifter 10 compensates for the phase shift of the feedback voltage e ad and feeds back to the feedback amplifier 7 a feedback voltage e p that matches the phase of the output voltage e 0 of the feedback amplifier 7 .
移相器１０の動作を説明する。移相器１０から
の前記帰還電圧epは次式で表わされる。 The operation of phase shifter 10 will be explained. The feedback voltage e p from the phase shifter 10 is expressed by the following equation.
ep＝ead（R4−z2／z1＋z2R4−R3z2／z1＋z2）／R4…(3) (3)式において、R3＝R4に設定すると、 ep＝ead（１−2z2／z1＋z2） …(4) 但し、 ep：移相器１０の帰還電圧、 ead：加算器９の出力電圧、 z1：可変抵抗R5のインピーダンス、 z2：コンデンサＣのインピーダンス。e p = e ad (R 4 - z 2 / z 1 + z 2 R 4 - R 3 z 2 / z 1 + z 2 ) / R 4 ...(3) In equation (3), if R 3 = R 4 , , e p = e ad (1-2z 2 /z 1 + z 2 ) ...(4) where, e p : feedback voltage of phase shifter 10, e ad : output voltage of adder 9, z 1 : variable resistor R 5 impedance, z 2 : impedance of capacitor C.
(4)式から明らかなように、移相器１０からの帰
還電圧epの位相は、移相器１０の増幅度（R4／
R3）が１であるので、可変抵抗R5の値を変化さ
せることによつて任意に調整することができる。
これによつて、帰還増幅器９の出力電圧e0の位相
と、加算器９からの帰還電圧eadとの位相を一致
させることができる。 As is clear from equation (4), the phase of the feedback voltage e p from the phase shifter 10 is determined by the amplification degree of the phase shifter 10 (R 4 /
Since R 3 ) is 1, it can be arbitrarily adjusted by changing the value of variable resistor R 5 .
Thereby, the phase of the output voltage e 0 of the feedback amplifier 9 and the phase of the feedback voltage e ad from the adder 9 can be matched.
移相器１０の可変抵抗R5の値を、帰還増幅器
９の出力電圧e0の位相と、加算器９からの帰還電
圧eadとの位相とが一致するように調整するには、
以下のようにする。例えば、帰還増幅器７が、発
振器６の出力電圧eiの位相と帰還増幅器７の出力
電圧e0の位相とが180度ずれているときに最も効
率よく作動するものであるときには、前記出力電
圧eiおよびe0を各々、例えば位相計で測定し、こ
れらの間の位相差が180度となるように前記可変
抵抗R5の値を手動によつて調整する。 To adjust the value of the variable resistor R 5 of the phase shifter 10 so that the phase of the output voltage e 0 of the feedback amplifier 9 matches the phase of the feedback voltage e ad from the adder 9,
Do as follows. For example, if the feedback amplifier 7 operates most efficiently when the phase of the output voltage e i of the oscillator 6 and the phase of the output voltage e 0 of the feedback amplifier 7 are out of phase by 180 degrees, the output voltage e i and e 0 are each measured using, for example, a phase meter, and the value of the variable resistor R 5 is manually adjusted so that the phase difference between them is 180 degrees.
次に、この発明の他の実施態様を図面を参照し
ながら説明する。 Next, other embodiments of the invention will be described with reference to the drawings.
この実施態様は、位相補償を自動的に行う点が
前述した実施態様と異なる。 This embodiment differs from the previously described embodiment in that phase compensation is automatically performed.
第４図は、この発明の他の実施態様の概略構成
図である。 FIG. 4 is a schematic diagram of another embodiment of the present invention.
第４図において、位相検波器１１は発振器６の
出力電圧eiと帰還増幅器７の出力電圧e0との位相
差に対応した直流制御電圧ECを位相制御器１２
の一方の入力端子Ｘに供給する。位相制御器１２
は掛算器１３と、掛算器１３の他方の入力端子Ｙ
と出力端子ｚとの間に接続したコンデンサＣとか
らなる。移相制御器１２の入力端子Ｙには移相器
１０の一方の入力電圧ｅが加えられ、入力端子ｘ
には位相検波器１１からの制御電圧ECが加えら
れる。掛算器１３の出力電圧eMは、
eM＝Ｋ・ｅ・EC …(5)
但し、
Ｋ：掛算器１３の定数
となるから、制御電圧ECの値が変化すると、コ
ンデンサＣの両端子間の電圧差（ｅ−eM）が変化
し、このためにコンデンサＣを流れる電流の値が
変わる。 In FIG. 4, a phase detector 11 outputs a DC control voltage E C corresponding to the phase difference between the output voltage e i of the oscillator 6 and the output voltage e 0 of the feedback amplifier 7 to a phase controller 12.
is supplied to one input terminal X of the . Phase controller 12
is the multiplier 13 and the other input terminal Y of the multiplier 13
and a capacitor C connected between the output terminal z and the output terminal z. One input voltage e of the phase shifter 10 is applied to the input terminal Y of the phase shift controller 12, and the input terminal x
A control voltage E C from the phase detector 11 is applied to. The output voltage e M of the multiplier 13 is: e M =K・e・E C …(5) However, since K is a constant of the multiplier 13, when the value of the control voltage E C changes, both ends of the capacitor C The voltage difference between the capacitors (e-e M ) changes and therefore the value of the current flowing through capacitor C changes.
従つて、制御電圧ECの変化に応じてコンデン
サＣの容量は等価的に変化する。 Therefore, the capacitance of the capacitor C changes equivalently in response to a change in the control voltage E.sub.C.
例えば、掛算器１３の定数Ｋを1/10とすると、
制御電圧ECに対するコンデンサＣの等価容量Ce
は、第５図に示されるような特性となる。 For example, if the constant K of the multiplier 13 is 1/10,
Equivalent capacitance C e of capacitor C for control voltage E C
has the characteristics as shown in FIG.
このように、コンデンサＣの容量が制御電圧
ECに応じて変化すれば、(4)式から明らかなよう
に、移相器１０は加算器９の帰還電圧eadの位相
を自動的に補償して、帰還増幅器７の出力電圧e0
の位相と一致した帰還電圧epを帰還増幅器７に帰
還する。 In this way, the capacitance of capacitor C is equal to the control voltage
As is clear from equation (4), the phase shifter 10 automatically compensates the phase of the feedback voltage e ad of the adder 9, and the output voltage e 0 of the feedback amplifier 7 changes according to E C.
A feedback voltage e p matching the phase of is fed back to the feedback amplifier 7.
第６図に上述したこの発明に従つて帰還回路網
内の位相偏移を補償したときの帰還増幅器の出力
特性を示す。 FIG. 6 shows the output characteristics of the feedback amplifier when the phase shift in the feedback network is compensated for according to the invention described above.
第６図から明らかなように、この発明によれ
ば、帰還回路網内に移相偏移が生じても位相偏移
がない場合の出力特性と同様な出力特性を得るこ
とができる。 As is clear from FIG. 6, according to the present invention, even if a phase shift occurs in the feedback network, output characteristics similar to those obtained when there is no phase shift can be obtained.
以上説明したように、この発明によれば、帰還
回路網内で帰還電圧の位相偏移が生じても溶鋼面
レベルを正確に計測することができるといつたき
わめて有用な効果がもたらされる。 As described above, the present invention provides extremely useful effects such as being able to accurately measure the level of the molten steel even if a phase shift of the feedback voltage occurs within the feedback network.
第１図は、従来の渦流式湯面計の概略構成図、
第２図は、溶鋼面レベルと検出ヘツドとの間の距
離ｌと出力電圧e0との関係を示すグラフ、第３図
は、この発明の一実施態様の概略構成図、第４図
は、この発明の他の実施態様の概略構成図、第５
図は、制御電圧ECとCe／Ｃとの関係を示すグラ
フ、第６図は、溶鋼面レベルと検出ヘツドとの間
の距離ｌと出力電圧e0との関係を示すグラフであ
る。図面において、
１……モールド、２……溶鋼、３……検出ヘツ
ド、４……１次コイル、５ａ，５ｂ……２次コイ
ル、６……発振器、７……帰還増幅器、８……差
動増幅器、９……加算器、１０……移相器、１１
……位相検波器、１２……位相制御器、１３……
掛算器。
Figure 1 is a schematic configuration diagram of a conventional eddy current water level gauge.
FIG. 2 is a graph showing the relationship between the distance l between the molten steel surface level and the detection head and the output voltage e0 , FIG. 3 is a schematic diagram of an embodiment of the present invention, and FIG. Schematic configuration diagram of another embodiment of this invention, No. 5
This figure is a graph showing the relationship between the control voltage E C and C e /C, and FIG. 6 is a graph showing the relationship between the distance l between the molten steel surface level and the detection head and the output voltage e 0 . In the drawings, 1...mold, 2...molten steel, 3...detection head, 4...primary coil, 5a, 5b...secondary coil, 6...oscillator, 7...feedback amplifier, 8...difference dynamic amplifier, 9... adder, 10... phase shifter, 11
... Phase detector, 12 ... Phase controller, 13 ...
Multiplier.
Claims (1)
れた検出ヘツドの前記１次コイルに帰還増幅器か
ら交流電圧を加え、これによつて前記１対の２次
コイルに生じた誘起電圧の各々の差を差動増幅器
によつて演算し、前記差電圧と前記帰還増幅器の
出力電圧とを加算器によつて加算し、前記加算電
圧を前記帰還増幅器に帰還することからなる渦流
式湯面レベル測定法において、 前記帰還増幅器に帰還する帰還電圧の位相を、
移相器によつて前記帰還増幅器の出力電圧の位相
と一致させることを特徴とする渦流式湯面レベル
測定法。[Claims] 1. An alternating current voltage is applied from a feedback amplifier to the primary coil of the detection head, which is composed of a primary coil and a pair of secondary coils, thereby applying an alternating current voltage to the pair of secondary coils. The difference between the induced voltages generated is calculated by a differential amplifier, the difference voltage and the output voltage of the feedback amplifier are added by an adder, and the added voltage is fed back to the feedback amplifier. In the eddy current type water level measurement method, the phase of the feedback voltage fed back to the feedback amplifier is
An eddy current type hot water level measuring method characterized in that the phase of the output voltage of the feedback amplifier is matched with the phase of the output voltage of the feedback amplifier using a phase shifter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19991983A JPS6093316A (en) | 1983-10-27 | 1983-10-27 | Eddy current type hot water level measuring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19991983A JPS6093316A (en) | 1983-10-27 | 1983-10-27 | Eddy current type hot water level measuring method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6093316A JPS6093316A (en) | 1985-05-25 |
| JPH0242416B2 true JPH0242416B2 (en) | 1990-09-21 |
Family
ID=16415778
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19991983A Granted JPS6093316A (en) | 1983-10-27 | 1983-10-27 | Eddy current type hot water level measuring method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6093316A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2945118B1 (en) * | 2009-04-29 | 2011-06-17 | Avemis | SENSOR AND METHOD FOR MEASURING THE LEVEL OF THE SURFACE OF A LIQUID PHASE METAL |
| JP2013154394A (en) * | 2012-01-31 | 2013-08-15 | Shinagawa Refractories Co Ltd | Eddy current mold level sensor |
| JP2013154393A (en) * | 2012-01-31 | 2013-08-15 | Shinagawa Refractories Co Ltd | Molten metal level gauge in mold for continuous casting, and molten metal level control method using the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5612502A (en) * | 1979-07-12 | 1981-02-06 | Nippon Kokan Kk <Nkk> | Feedback amplification type vortex flow range finder |
| JPS57192805A (en) * | 1981-05-25 | 1982-11-27 | Nippon Kokan Kk <Nkk> | Differential feedback type eddy current distance meter |
-
1983
- 1983-10-27 JP JP19991983A patent/JPS6093316A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6093316A (en) | 1985-05-25 |
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