JPS58205820A - Liquid level sensor - Google Patents
Liquid level sensorInfo
- Publication number
- JPS58205820A JPS58205820A JP8877682A JP8877682A JPS58205820A JP S58205820 A JPS58205820 A JP S58205820A JP 8877682 A JP8877682 A JP 8877682A JP 8877682 A JP8877682 A JP 8877682A JP S58205820 A JPS58205820 A JP S58205820A
- Authority
- JP
- Japan
- Prior art keywords
- liquid
- liquid level
- thin plate
- level sensor
- sensor
- 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.)
- Pending
Links
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
- G01F23/28—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 the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/296—Acoustic waves
- G01F23/2966—Acoustic waves making use of acoustical resonance or standing waves
Abstract
Description
【発明の詳細な説明】
この発明は液面センサーに関し、工り具体的には圧電体
を使用した液面センサーに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid level sensor, and specifically relates to a liquid level sensor using a piezoelectric material.
従来より使用されてｈる液面センサーとしては、電極相
互間の静電容量変化を検出する静電容量方式や、超音波
の発振から受信までの時間的変化を検出する超音波方式
あるいは空胴のポールとその内部に水銀スイッチ等を内
臓させポールの浮力により液面レベルを検出するポール
スイッチ方式等が提供されている。Conventionally used liquid level sensors include a capacitive type that detects changes in capacitance between electrodes, an ultrasonic type that detects temporal changes from ultrasonic oscillation to reception, and a cavity type that detects changes in capacitance between electrodes. There is a pole switch method that detects the liquid level using the buoyancy of the pole, which has a mercury switch built into the pole.
しかしながらこれらの従来の液面センサーにあっては、
静電容量方式においては測定すべき対象物や異物が電極
に耐着し測定誤差が生じるという問題や、超音波方式に
おいては、測定対酸物の投入音や温度差にｚ６測定誤差
が生じなり、浮遊異物により超音波が反射されるという
問題や、ボールスイッチ方式にあっては、ボールの浮力
を利用するためポールがか々り大きく液面センサーとし
て取付ける場所的制約を受けるという問題があった。こ
の発明は上記のような従来の液面センサーの種々の問題
点に鑑みなされ大もので、その目的とするところは、チ
タン酸バリウムや水晶等からなる圧電体を金属製の弾性
薄板上に貼着し振動体となし、この振動体を所定形状ヲ
有するセンサーケース内に収容し、前記弾性薄板下面を
任意の液体に接触せしめるＩうにして液面センサーとな
すことにより、測定対象物中に異物等が混入されてｂて
も極めて安定した性能を発揮し且つ堅牢で、コンパクト
な液面センサーを提供することを目的とするものである
。However, with these conventional liquid level sensors,
In the capacitive method, there is a problem that the object to be measured or foreign matter adheres to the electrode, causing measurement errors.In the ultrasonic method, there is a problem in that measurement errors occur due to the noise and temperature difference between the acid and the acid being added. There were problems with ultrasonic waves being reflected by floating foreign objects, and with the ball switch method, there were problems with the use of the buoyancy of the ball, which meant that the pole was large and restricted in the location where it could be installed as a liquid level sensor. . This invention was developed in view of the various problems of conventional liquid level sensors as described above, and its purpose is to attach a piezoelectric material made of barium titanate, crystal, etc. to an elastic thin plate made of metal. This vibrating body is housed in a sensor case having a predetermined shape, and the lower surface of the elastic thin plate is brought into contact with any liquid to form a liquid level sensor. The object of the present invention is to provide a compact liquid level sensor that exhibits extremely stable performance even when foreign matter is mixed in, and is robust and compact.
以下にこの発明の好適な実施例について図面を参照し説
明する。Preferred embodiments of the present invention will be described below with reference to the drawings.
第１図はこの発明に係る液面センサー全使用し、液面変
位を電気的信号に変換する場合を示すもので、左側に液
面センサ一部Ａがタンク等の液体容器側壁面に取付けら
れた状態の断面を示し、右側の破線内に検出回路部Ｂを
ブロック線図で示すものである。Figure 1 shows a case in which all of the liquid level sensors according to the present invention are used and liquid level displacement is converted into electrical signals. The cross section is shown in a state in which the detection circuit section B is shown in a block diagram within the broken line on the right side.
この実施例においては、金属あるいは硬質グラスチック
等よりなるセンサーケース１は７ランシ状に形成され、
センサーケース１のフランジ鍔の一側端には、円形の金
属等から々る弾性薄板２がその周縁部をセンサーケース
１に固着されている。In this embodiment, a sensor case 1 made of metal or hard glass is formed into a 7-run shape,
At one end of the flange collar of the sensor case 1, a circular elastic thin plate 2 made of metal or the like is fixed to the sensor case 1 at its peripheral edge.
前記弾性薄板２の上面には、チタン酸バリウムや水晶等
からなる圧電体８が蒸着等により貼着されており、弾性
薄板２と圧電体８とで振動体４を構成している。A piezoelectric body 8 made of barium titanate, crystal, or the like is adhered to the upper surface of the elastic thin plate 2 by vapor deposition or the like, and the elastic thin plate 2 and the piezoelectric body 8 constitute a vibrating body 4.
そしてこの振動体４の振動変化を感知すべくこの実施例
においては、前記弾性薄板２上と前記圧電体Ｂ上に設け
られた主端子５が、後述する検出回路部Ｂ内の第１の増
幅器２０の出力側と接続され、さらに前記圧電体３上に
設けられたフィードバック端子６が第１の増幅器２０の
入力側に接続され発振器を構成している。これらの端子
と増幅器２０間の接続は絶縁被覆されたリード、線７で
なされている。In this embodiment, in order to sense the vibration change of the vibrating body 4, the main terminal 5 provided on the elastic thin plate 2 and the piezoelectric body B is connected to a first amplifier in a detection circuit section B, which will be described later. A feedback terminal 6 provided on the piezoelectric body 3 is further connected to the input side of the first amplifier 20 to constitute an oscillator. Connections between these terminals and the amplifier 20 are made by insulated leads or wires 7.
前記センサーケース１け、タンク等の容器側壁面８を貫
通して取付けられ、センサーケース１のフランジ鍔部と
容器側壁面８との間には、０リング９が挿入されており
前記センサーケース１の首部に周設され大雄ねじと螺合
するナラ、）ＩＯＱ締めつけることに工す、容器内部の
液体１１の漏出全防止している。The sensor case 1 is attached by penetrating the side wall surface 8 of a container such as a tank, and an O-ring 9 is inserted between the flange flange of the sensor case 1 and the side wall surface 8 of the container. The neck of the container, which is fitted around the neck of the container and screwed into the large male screw, is designed to tighten the IOQ, completely preventing leakage of the liquid 11 inside the container.
更にこの実施例においては、前記センサーケース１の後
端部には、前記リード線７が貫通されゴム等のシール材
１２が固着され、前記センサーケース１内を水蜜状態に
保ち、容器内の液体１１の漏出を厳重に防止している。Further, in this embodiment, the lead wire 7 is passed through the rear end of the sensor case 1, and a sealing material 12 such as rubber is fixed to the rear end of the sensor case 1 to keep the inside of the sensor case 1 in a wet state and to prevent the liquid in the container. 11 leakage is strictly prevented.
次に検出回路部８の説明をすると、前記弾性薄板２と圧
電体８及び第１の増幅器２０とで構成される発振器の出
力は、波形整形回路２１ヲ介してワンショットマルチバ
イブレータ−等で構成され一定間隔の基準信号を発生す
る基準信号発生回路２２と、ＡＮＤ回路回路リフリップ
フロップ回路構成される位相検出回路２３とに入力され
、前記基準信号発生回路２２の出力信号に位相検出回路
２３のＡＮＤ回路に入力されている。Next, the detection circuit section 8 will be explained. The output of the oscillator composed of the elastic thin plate 2, the piezoelectric body 8, and the first amplifier 20 is transmitted via a waveform shaping circuit 21 to a one-shot multivibrator or the like. The output signal of the reference signal generating circuit 22 is inputted to a reference signal generating circuit 22 that generates reference signals at regular intervals, and a phase detecting circuit 23 that is constituted of an AND circuit flip-flop circuit. It is input to an AND circuit.
そして位相検出回路２３の出力に、第２の増幅器２４を
介して外部に送出される。この実施例における液面セン
サーの動作及び検出信号がとの工うに送出されるかにつ
いて説明すると、まず前記弾性薄板２と圧電体８とで構
成される振動体４の動作であるが、この振動体４は弾性
薄板２の下面に接触する媒質によって共振周波数を異に
する。The output of the phase detection circuit 23 is then sent to the outside via the second amplifier 24. To explain the operation of the liquid level sensor and how the detection signal is sent out in this embodiment, first, the operation of the vibrating body 4 composed of the elastic thin plate 2 and the piezoelectric body 8 will be explained. The body 4 has different resonance frequencies depending on the medium that contacts the lower surface of the elastic thin plate 2.
従って振動体４と前記第１の増幅器２０とで構成された
発族器の発振周波数が異なることになる。Therefore, the oscillation frequencies of the oscillator composed of the vibrating body 4 and the first amplifier 20 are different.
この状態は第２図に示すものであり、同図におけるｆｏ
は前記弾性薄板２に接触する媒質が空気の共振周波数を
示すものであり、ｆ、は水や油等の液体が接触した場合
の共振周波数を示すものである。This state is shown in Figure 2, where fo
indicates the resonance frequency of air as the medium that contacts the elastic thin plate 2, and f indicates the resonance frequency when a liquid such as water or oil comes into contact with it.
このように弾性薄板に液体が接触することにより、共振
周波数がΔｆだけ低く々る。When the liquid comes into contact with the elastic thin plate in this way, the resonance frequency decreases by Δf.
そしてこの状態は波形整形回路２１により整形され基準
信号発生回路２２及び位相検出回路２３に入力される。This state is then shaped by the waveform shaping circuit 21 and input to the reference signal generation circuit 22 and phase detection circuit 23.
基準信号発生回路は、波形整形回路２１からの信号を受
けある一定の時間（１，）遅れて、一定間隔の基準信号
Ｓｏ’ｊｉ７ＡＮＤ回路を介して位相検出回路２３に送
出する。The reference signal generation circuit receives the signal from the waveform shaping circuit 21, is delayed by a certain period of time (1,), and sends the signal to the phase detection circuit 23 via the reference signal So'ji7AND circuit at a certain interval.
この状態は第８図に示すものであり、同図において日１
は前記弾性薄板２が空気に接して因る場合の、波形整形
後の状態を示すものであり、Ｓ２は、液体が接触した場
合の状態を示すものである。This state is shown in Figure 8, in which day 1
S2 shows the state after waveform shaping when the elastic thin plate 2 is in contact with air, and S2 shows the state when it is in contact with liquid.
そしてＳＯは、基準信号を示すものでありＳは位相検出
回路２３の出力を示すものである。Further, SO indicates a reference signal, and S indicates an output of the phase detection circuit 23.
この位相検出回路２３の出力は、入力回路が基準信号発
生回路２２と波形整形回路２２のＡＮＤ ’（ｉ７とっ
ている大め、図に示すように弾性薄板２が空気に接触し
ている場合には出力は送出されず、液面に接し大場合に
ついてのみ出力信号を送出することになる。The output of this phase detection circuit 23 is determined by the input circuit being an AND' (i7) of the reference signal generation circuit 22 and the waveform shaping circuit 22. No output will be sent out, and an output signal will be sent out only when the liquid surface is in contact with the liquid surface.
この位相検出回路２３の出力信号の状態は第４図に示す
ものである。このようにして液面センサーが任意の液体
に接触することにより、電気信号が外部の制御装置や表
示装置に送出されることになる。The state of the output signal of this phase detection circuit 23 is shown in FIG. When the liquid level sensor comes into contact with any liquid in this way, an electrical signal is sent to an external control device or display device.
伺この実施例においては、タンク等の容器側壁面に液面
センサーを取り付けた場合について説明したが、この考
案に係る液面センサーがこれに限定されるものでなく、
容器の上面に取り付けること等も可能であることはいう
までもない。In this embodiment, a case has been described in which a liquid level sensor is attached to the side wall of a container such as a tank, but the liquid level sensor according to this invention is not limited to this.
It goes without saying that it is also possible to attach it to the top surface of the container.
以上の工うにこの発明に係る液面センサーは、チタン酸
バリウムや水晶等からなる圧電体を金属製の弾性板上面
に貼着し振動体となし、この振動体を所定形状を有する
センサーケース内に収納し、前記弾性薄板下面を任意の
液体に接触せしめるようにしてなると−う極めて簡単な
構造を有する液面センサーであり、堅牢でコンパクトな
故センサーの取付は場所の制限がないばかりでなく、経
済性にも優れ且つ被測定対象物中に浮遊物等の混入があ
った場合においても、液体に接触している弾性薄板が微
細に振動しているため測定面に異物の耐着は全く発生せ
ず測定誤差の少ない極めて安定した動作を示すものであ
る。As described above, the liquid level sensor according to the present invention has a piezoelectric material made of barium titanate, crystal, etc. attached to the upper surface of a metal elastic plate to serve as a vibrating body, and this vibrating body is placed inside a sensor case having a predetermined shape. It is a liquid level sensor with an extremely simple structure that allows the lower surface of the thin elastic plate to come into contact with any liquid.Since it is robust and compact, there are no restrictions on where it can be installed. , is highly economical, and even if there is floating matter mixed into the object to be measured, the thin elastic plate in contact with the liquid vibrates minutely, so there is no resistance to foreign matter adhering to the measurement surface. This shows an extremely stable operation with no errors and little measurement error.
更には液体中に電気を通じるものでないためガソリンや
油等の可燃性液体に対しても使用でき、弾性薄板の材質
の選択や保護膜を貼着する等により耐腐食性にすぐれた
液面センサーが提供されるものである。Furthermore, since electricity does not pass through the liquid, it can also be used for flammable liquids such as gasoline and oil, and the liquid level sensor has excellent corrosion resistance due to the selection of the material of the elastic thin plate and the attachment of a protective film. is provided.
第１図はこの発明に係る液面センサーを示す断面図と液
面変位の検出回路部を示すブロック線図である。第２図
はこの発明に係る液面センサーの共振周波数の変化を示
すものであり、第８図は波形整形後の各部の信号レベル
を示すものであり、第４図は外部に対して送出される電
気信号のレベルを示すものである。
第１図において
１・・・センサーケース
２・・・弾性薄板
８・・・圧電体
４・・・振動体
７・・・リード線
８・・・容器側壁面
９・・・０リング
１１・・・液面
２０・・・第１の増幅器
２１・・・波形整形回路
２２・・・基準信号発生回路
２３・・・位相検出回路
２４・・・第２の増幅器
特 許 出 願 人 富士電気化学株式会社（１１）
１０２−
Ｎ
ンFIG. 1 is a sectional view showing a liquid level sensor according to the present invention and a block diagram showing a liquid level displacement detection circuit section. Figure 2 shows changes in the resonant frequency of the liquid level sensor according to the present invention, Figure 8 shows the signal levels of various parts after waveform shaping, and Figure 4 shows the signal levels sent to the outside. This indicates the level of the electrical signal. In Fig. 1, 1... Sensor case 2... Elastic thin plate 8... Piezoelectric body 4... Vibrating body 7... Lead wire 8... Container side wall surface 9... O-ring 11...・Liquid level 20...First amplifier 21...Waveform shaping circuit 22...Reference signal generation circuit 23...Phase detection circuit 24...Second amplifier Patent Applicant: Fuji Electrochemical Co., Ltd. Company (11) 102- N
Claims (1)
金属製の弾性薄板上面に貼着し振動体となし、該振動体
を所定形状を有する １５ノセンサーケース内に収納し、該弾性薄板下面を任
意の液体に接触せしめる工うに・してなることを特徴と
する液面センサー。 （２）前記振動体と前記弾性薄板下面に接触される任意
の液体との共振周波数を電気的手段を介して検知するよ
うにしてなることを特徴とする特許請求の範囲第１項記
載の液面センサ０ （８） 前記弾性薄板下面が接触する液体に対抗し得
る保護膜を貼着し前記弾性薄板となすことを特徴とする
特許請求の範囲第１項または第２項記載の液面センサー
。 （４）前記振動体の前記圧電体を含まな込弾性薄板部を
前記センサーケースに固定してなることを特徴とする特
許請求の範囲第１項または第２項または第８項記載の液
面センサー。[Scope of Claims] (1) A piezoelectric material made of barium titanate, crystal, etc. is adhered to the upper surface of a thin metal elastic plate to form a vibrating body, and the vibrating body is housed in a 15-inch sensor case having a predetermined shape. A liquid level sensor characterized in that the lower surface of the elastic thin plate is brought into contact with any liquid. (2) The liquid according to claim 1, wherein the resonance frequency of the vibrating body and any liquid that comes into contact with the lower surface of the elastic thin plate is detected through electrical means. Surface sensor 0 (8) The liquid level sensor according to claim 1 or 2, characterized in that the elastic thin plate is formed by pasting a protective film capable of resisting the liquid that comes into contact with the lower surface of the elastic thin plate. . (4) The liquid level according to claim 1, 2, or 8, characterized in that an elastic thin plate portion including the piezoelectric body of the vibrating body is fixed to the sensor case. sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8877682A JPS58205820A (en) | 1982-05-27 | 1982-05-27 | Liquid level sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8877682A JPS58205820A (en) | 1982-05-27 | 1982-05-27 | Liquid level sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS58205820A true JPS58205820A (en) | 1983-11-30 |
Family
ID=13952250
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8877682A Pending JPS58205820A (en) | 1982-05-27 | 1982-05-27 | Liquid level sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58205820A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6384522U (en) * | 1986-11-21 | 1988-06-02 | ||
| US5035140A (en) * | 1988-11-03 | 1991-07-30 | The Boeing Company | Self cleaning liquid level detector |
| US5267474A (en) * | 1992-10-23 | 1993-12-07 | Kohler Co. | Liquid-level sensor |
| CH683375A5 (en) * | 1991-10-01 | 1994-02-28 | Vibro Meter Ag | Detecting presence, level or condition of fluid - using evaluation circuit to register frequency of diaphragm inserted flush into wall of vessel |
| US6729184B2 (en) * | 2000-07-28 | 2004-05-04 | Seiko Epson Corporation | Detector of liquid consumption condition |
| US6745626B2 (en) | 1999-05-20 | 2004-06-08 | Seiko Epson Corporation | Liquid detecting piezoelectric device, liquid container and mounting module member |
| US6793305B2 (en) | 2000-05-18 | 2004-09-21 | Seiko Epson Corporation | Method and apparatus for detecting consumption of ink |
-
1982
- 1982-05-27 JP JP8877682A patent/JPS58205820A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6384522U (en) * | 1986-11-21 | 1988-06-02 | ||
| US5035140A (en) * | 1988-11-03 | 1991-07-30 | The Boeing Company | Self cleaning liquid level detector |
| CH683375A5 (en) * | 1991-10-01 | 1994-02-28 | Vibro Meter Ag | Detecting presence, level or condition of fluid - using evaluation circuit to register frequency of diaphragm inserted flush into wall of vessel |
| US5267474A (en) * | 1992-10-23 | 1993-12-07 | Kohler Co. | Liquid-level sensor |
| US6745626B2 (en) | 1999-05-20 | 2004-06-08 | Seiko Epson Corporation | Liquid detecting piezoelectric device, liquid container and mounting module member |
| US6799820B1 (en) | 1999-05-20 | 2004-10-05 | Seiko Epson Corporation | Liquid container having a liquid detecting device |
| US7251996B2 (en) | 1999-05-20 | 2007-08-07 | Seiko Epson Corporation | Liquid detecting piezoelectric device, liquid container and mounting module member |
| US6793305B2 (en) | 2000-05-18 | 2004-09-21 | Seiko Epson Corporation | Method and apparatus for detecting consumption of ink |
| US6729184B2 (en) * | 2000-07-28 | 2004-05-04 | Seiko Epson Corporation | Detector of liquid consumption condition |
| US7086281B2 (en) * | 2000-07-28 | 2006-08-08 | Seiko Epson Corporation | Detector of liquid consumption condition |
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