JPS5919816A - Level gauge - Google Patents
Level gaugeInfo
- Publication number
- JPS5919816A JPS5919816A JP12969482A JP12969482A JPS5919816A JP S5919816 A JPS5919816 A JP S5919816A JP 12969482 A JP12969482 A JP 12969482A JP 12969482 A JP12969482 A JP 12969482A JP S5919816 A JPS5919816 A JP S5919816A
- Authority
- JP
- Japan
- Prior art keywords
- diaphragm
- liquid
- liquid level
- container
- piezoelectric ceramics
- 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
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Description
【発明の詳細な説明】
（発明の性質、目的）
この発明は、容器内の液面位置を知るための液面計に関
し、外から見えない容器内の液面位置を示す電気信号を
得て、容器内の液の有無、液量を知ることのできる液面
計を得ることを目的とした発明である。Detailed Description of the Invention (Nature and Object of the Invention) The present invention relates to a liquid level gauge for determining the liquid level position in a container, and the present invention relates to a liquid level gauge that obtains an electric signal indicating the liquid level position in the container that is not visible from the outside. This invention aims to provide a liquid level gauge that can determine the presence or absence of liquid in a container and the amount of liquid.
（従来技術）
液面語としては、容器壁忙透明窒を設けまたは容器内に
通じる透明管を容器壁に平行に突設して液面位置を直接
見たり、浮子の昇降を介して電気的または機械的手段に
より間接的に液面位置を知るものが実用されて来たが、
透明窓等による液面側は透明窓等の汚れにより視界が回
部になったり、視察位置が限定されるので不便であり、
浮子を利用する液面用は、設置するために複雑な機構を
設けなければならない等の不便がある。(Prior art) To measure the liquid level, it is possible to directly observe the liquid level by installing transparent nitrogen on the container wall or by protruding a transparent tube leading into the container parallel to the container wall, or by raising and lowering a float to check the liquid level. Alternatively, devices that indirectly know the liquid level position by mechanical means have been put into practical use.
It is inconvenient to use a transparent window on the liquid surface side because dirt on the transparent window can cause the visibility to be limited and the viewing position to be limited.
Liquid level floats that use floats have the inconvenience of requiring a complicated mechanism for installation.
（本発明の構成）
この発明は、容器壁に取付けた受感部の振動板に圧電セ
ラミックを固着し、これに電気的なパルス信号を加えて
振動板を加振し、その減衰状態が振動板に作用する液圧
により変化する現象を利用して、減衰状態を電気量とし
て検知し液面位置を知るようにして液面計を構成したも
のである。(Structure of the present invention) In this invention, a piezoelectric ceramic is fixed to a diaphragm of a sensing part attached to a container wall, and an electric pulse signal is applied to the diaphragm to excite the diaphragm. The liquid level gauge is constructed so that the damping state is detected as an electrical quantity by utilizing the phenomenon that changes due to the liquid pressure acting on the plate, and the liquid level position is determined.
第１図は液１を入れた容器２に本発明の液面計の受感部
３を取付けた状態を略示し、第２図は受感部の構造およ
び取付は方の詳細を例示する。FIG. 1 schematically shows a state in which a sensing section 3 of a liquid level gauge according to the present invention is attached to a container 2 containing a liquid 1, and FIG. 2 illustrates details of the structure and attachment of the sensing section.
第２図において、一端に７ランジ４を形成した金属の螺
管５のフランジの外面（液に接する而）に、厚さ０．５
Ｘ程度のステンレス鋼板の振動板６を周縁部を溶接して
固定し、その内面Ｃ液に接しない而）に圧電セラミック
７を接着する。この螺管５を容器２の孔８に容器内から
挿通して７ランジ４を容器内面に当接させ、容器外から
ナツト９を緊締して螺管５を容器壁に −取付ける。１
０は液密のためフランジの内面に形成した円形溝に挿入
した輪状バッキングで、容器内の液が孔８から漏出しな
いようにする。In FIG. 2, the outer surface of the flange (in contact with the liquid) of a metal spiral tube 5 with seven flange 4 formed at one end has a thickness of 0.5 mm.
A diaphragm 6 made of a stainless steel plate with a size of about This spiral tube 5 is inserted into the hole 8 of the container 2 from inside the container, the 7 flange 4 is brought into contact with the inner surface of the container, and the screw tube 5 is attached to the container wall by tightening the nut 9 from outside the container. 1
0 is a ring-shaped backing inserted into a circular groove formed on the inner surface of the flange for liquid-tightness, and prevents the liquid in the container from leaking from the hole 8.
７ランジ４の容器壁に当接する面は、容器壁に合致する
形状に形成する。振動板６の周縁部は、７ランジ４に溶
接されるので、この部分からの漏洩はない。１１は座金
である。圧電セラミック７の一極には導線１２を接続し
、他極は金属の螺管５に接続された導線１３にステンレ
スの振動板を介して接続される。7. The surface of the flange 4 that comes into contact with the container wall is formed into a shape that matches the container wall. Since the peripheral portion of the diaphragm 6 is welded to the 7 flange 4, there is no leakage from this portion. 11 is a washer. A conductive wire 12 is connected to one pole of the piezoelectric ceramic 7, and the other pole is connected to a conductive wire 13 connected to a metal spiral tube 5 via a stainless steel diaphragm.
このように構成した受感部３の圧電セラミック７には、
第５〜６図の回路に示したような、約４ ＫＨｚ、パル
ス幅１０μｓ氏程度のパルス信号を周期的に発振する発
振器１４の出力な昇圧トランス１５で約３０Ｖ程度尾昇
圧して、導線１２．１３により印加する。このパルス信
号により圧電セラミック７が機械的に変位Ｐ （第３〜
４図）を生じ、これに駆動されて振動板６が振動する。The piezoelectric ceramic 7 of the sensing section 3 configured in this way has the following features:
As shown in the circuits of FIGS. 5 and 6, the output of an oscillator 14 which periodically oscillates a pulse signal of about 4 KHz and a pulse width of about 10 μs is boosted by about 30 V by a step-up transformer 15, and then the conductor 12 is Apply by .13. This pulse signal causes the piezoelectric ceramic 7 to be mechanically displaced P (3rd to
4), which causes the diaphragm 6 to vibrate.
この振動は振動板６の大きさ、厚さ、材質、圧電セラミ
ックの大きさ、液の比重、液の有無等の条件により定ま
る第３〜４図のような減衰振動Ｑ、Ｒとなる。This vibration becomes damped vibrations Q and R as shown in FIGS. 3 and 4, which are determined by conditions such as the size, thickness, and material of the diaphragm 6, the size of the piezoelectric ceramic, the specific gravity of the liquid, and the presence or absence of the liquid.
液１の量が少なくまたは無くて振動板６に液が接しない
場合は、第３図のように減衰振動の振幅が犬きく、振動
時間も長いが、振動板６に液圧が作用する場合は、第４
図のように振幅が小さく、振動時間も燈くなる。この場
合の振動は、液圧が大きい程、振幅が小さく、減衰が早
くなる。When the amount of liquid 1 is small or absent and the liquid does not come into contact with the diaphragm 6, the amplitude of the damped vibration is high and the vibration time is long, as shown in Figure 3, but when liquid pressure acts on the diaphragm 6. is the fourth
As shown in the figure, the amplitude is small and the vibration time is also light. In this case, the larger the hydraulic pressure, the smaller the amplitude and the faster the vibration damps.
この振動板６の振動状態は、振動板６と共に振動し微小
変形する圧電セラミック７の電気的出力として取出され
、第５〜６図の回路により増幅器に入力される。スイッ
チ１７は、発振器１４による電圧の大きなパルス信号を
圧電セラミック７に印加するときに、これが増幅器１６
に入って増幅器が破壊されるのを避けるために、パルス
信号印加時は開き、パルス発振が終りセラミック７の振
動による低電圧の出力が生じた段階で閉してこの出力を
増幅器】６に入力させるものである。増幅器１６で増幅
された圧電セラミック７の出力は、整流器１８で整流さ
れ積分器１９で整流波形の総面積を言１ｍされる。液が
振動板に接しないときの第３図の振動状態では、セラミ
ック７の出力は最も大きく減衰度も小さいので、このと
きの積分値Ａは大きく、液量が多くなって振動板６に加
わる液圧が高くなるに従ってこの積分値Ｂは小さくなる
。そこで第５図の回路により、セラミック７が大きく振
動す７．、）ときの積分値Ａを記憶器２０に記憶させて
おき、容器に液を入れたときの積分値Ｂと共に比較器２
１に入力して両種分値を比較すれば、液の有無を知るこ
とができる。この場合は、複数の受感部３を高さを変え
て容器壁に取付ければ、液面位置を段階的に知ることが
できる。The vibration state of the diaphragm 6 is extracted as an electrical output of the piezoelectric ceramic 7 which vibrates and is slightly deformed together with the diaphragm 6, and is input to an amplifier by the circuits shown in FIGS. 5 and 6. When the switch 17 applies a high-voltage pulse signal from the oscillator 14 to the piezoelectric ceramic 7, it is connected to the amplifier 16.
In order to avoid damage to the amplifier by entering the circuit, it opens when a pulse signal is applied, and closes when the pulse oscillation ends and a low voltage output is generated due to the vibration of the ceramic 7, and this output is input to the amplifier 6. It is something that makes you The output of the piezoelectric ceramic 7 that has been amplified by the amplifier 16 is rectified by the rectifier 18 and then by the integrator 19, where the total area of the rectified waveform is 1 m. In the vibration state shown in FIG. 3 when the liquid is not in contact with the diaphragm, the output of the ceramic 7 is the largest and the degree of attenuation is the smallest, so the integral value A at this time is large and a large amount of liquid is applied to the diaphragm 6. This integral value B becomes smaller as the hydraulic pressure becomes higher. Therefore, the circuit shown in FIG. 5 causes the ceramic 7 to vibrate greatly. , ) is stored in the memory 20, and is stored in the comparator 20 along with the integral value B when the liquid is poured into the container.
1 and compare both species values, it is possible to know the presence or absence of liquid. In this case, by attaching a plurality of sensing sections 3 to the container wall at different heights, the liquid level position can be known step by step.
第６図は１個の受感部で液面位置を連続的に知るように
構成した実施例の回路図を示す。容器に液を入Ａまたと
きの圧電セラミック７の出力の積分値Ｂを比較器２１に
入力することは前例同様である。セラミック７が最大に
振動するときの積分値Ａ ｉ１記憶器２０から減算器２
２に入り、別に減算器２２に入れられるサンプリング信
号Ｓと引算されて（Ａ−３）の出力が比較器２１に入れ
られ、積分値Ｂと比較される。第５図の回路は、最大の
積分値Ａを示す液面２Ｌ（第７図）を基準にして、測定
しようとする液面すが液面ａの上方にあるか否かを比較
器２１の出力により示すものであるが、第６図の回路は
、液面ａよりも上方にある液面Ｃを基準にして、これと
測定しようとする液面すとを比較し、測定しようとする
液面すがこれより上にあるか否かを知るようにしたもの
である。FIG. 6 shows a circuit diagram of an embodiment configured to continuously know the liquid level position using one sensing section. As in the previous example, the integrated value B of the output of the piezoelectric ceramic 7 when the liquid is poured into the container is inputted to the comparator 21. Integral value A when the ceramic 7 vibrates to its maximum value from the i1 memory 20 to the subtractor 2
2, the output of (A-3) is subtracted from the sampling signal S, which is separately input to the subtracter 22, and the output of (A-3) is input to the comparator 21, where it is compared with the integral value B. The circuit of FIG. 5 uses a comparator 21 to determine whether or not the liquid level to be measured is above the liquid level a, using the liquid level 2L (FIG. 7) showing the maximum integral value A as a reference. As shown by the output, the circuit in Figure 6 uses the liquid level C above the liquid level a as a reference, compares this with the liquid level to be measured, and calculates the liquid level to be measured. This allows you to know whether the face is above this level or not.
サンプリング信号Ｓの大きさを変えると、基準液面Ｃの
位置が変るから比較器２１の出力が０になったときのサ
ンプリング信号Ｓの大きさと、予め検定したこのサンプ
リング信号Ｓに対する液面位置とから、このときの液面
位置を知ることができろ。When the magnitude of the sampling signal S is changed, the position of the reference liquid level C changes, so the magnitude of the sampling signal S when the output of the comparator 21 becomes 0, and the liquid level position with respect to this sampling signal S, which has been verified in advance, are From this, you can find out the liquid level position at this time.
（本発明による効果）
この発明の液面用（マ、圧電セラミック７により振動板
６を加振し、次にその減衰振動をセラミック７の変形に
よる電気信号として取出すから、次のような効果がある
。(Effects of the present invention) The liquid surface use of the present invention (Ma) vibrates the diaphragm 6 with the piezoelectric ceramic 7, and then extracts the damped vibration as an electric signal due to the deformation of the ceramic 7, so the following effects can be obtained. be.
（１）電気的に液面を検知するから、液面の遠隔監視が
できる。(1) Since the liquid level is detected electrically, the liquid level can be monitored remotely.
（２）容器に対する加工は、受感：部３の取イ］けだけ
であり、受感部３を液密に容器に取付けることは容易で
ある。従って容器に対する加工は容易であり、透明窓等
を設けるよりも簡単である。(2) The only processing required for the container is the removal of the sensing section 3, and it is easy to attach the sensing section 3 to the container in a liquid-tight manner. Therefore, processing of the container is easy, and it is easier than providing a transparent window or the like.
（３） サンプリング信号を連続的に変化させること
により、液面位置を連続的に知ることができる。(3) By continuously changing the sampling signal, the liquid level position can be continuously determined.
（４）複数の受感部３は、寸法誤差、製作状態の相違等
のため固有の物理的、電気的性質に差ができても、サン
プリング信号を調整して減算器２２を作用させろことに
より、液面位置を示す出力のばらつきを容易に補正する
ことができる。(4) Even if there are differences in inherent physical and electrical properties of the plurality of sensing sections 3 due to dimensional errors, differences in manufacturing conditions, etc., the sampling signal can be adjusted to cause the subtracter 22 to act. , variations in the output indicating the liquid level position can be easily corrected.
図面はこの発明の実施例を示し、第１図は受感部を取（
ｑけた容器の略縦断面図、第２図は受感部の構造を示す
縦断面図、第３図は受感部が液に接しないときのセラミ
ックに加わるパルス変位およびこれにより振動するセラ
ミックの減衰振動出力を示す線図、第４図は振動板に液
圧が加わる場合の同様の線図、第５図は液面を検出する
回路図、第６図は別個の回路図、第７図は液面検知のた
めの基準液面を示す略図である。
１：液、２：容器、３：受感部、４：フランジ、５：螺
管、６：振動板、７：圧電セラミック、８：孔、９：ナ
ツト、１０：輪状パッキング、１１：座金、１２．１３
：導線、１４：発振器、１５：昇圧トランス、１６：増
幅器、１アニスインチ、１８：整流器、３９：積分器、
２０：記憶器、２１：比較器、２２：減算器。
特許出願人 株式会社千代田製作所
代 理 人 小 山 欽 造（
ほか１名）The drawings show an embodiment of the invention, and FIG. 1 shows the sensing part (
Figure 2 is a vertical cross-sectional view showing the structure of the sensing part, and Figure 3 shows the pulse displacement applied to the ceramic when the sensing part is not in contact with the liquid, and the resulting vibration of the ceramic. A diagram showing damped vibration output, Figure 4 is a similar diagram when liquid pressure is applied to the diaphragm, Figure 5 is a circuit diagram for detecting the liquid level, Figure 6 is a separate circuit diagram, Figure 7 is a schematic diagram showing a reference liquid level for liquid level detection. 1: Liquid, 2: Container, 3: Sensing part, 4: Flange, 5: Spiral tube, 6: Vibration plate, 7: Piezoelectric ceramic, 8: Hole, 9: Nut, 10: Ring-shaped packing, 11: Washer, 12.13
: Conductor, 14: Oscillator, 15: Step-up transformer, 16: Amplifier, 1 anis inch, 18: Rectifier, 39: Integrator,
20: Memory device, 21: Comparator, 22: Subtractor. Patent applicant: Kinzo Koyama, Managing Director, Chiyoda Manufacturing Co., Ltd.
1 other person)
Claims (1)
働する回路とから成る液面計であって、受感部（３）は
次の構成を有し、 （１） 圧電セラミック（７）を接着し自由に振動で
きる振動板（６）を取付けていること。 （ＩＩ） 容器壁に取付けられたとき容器内の液に接
触する振動板（６）により容器の内外を液密に仕切るこ
と。 （ＩＩ） 圧電セラミック（７）の電極に接続される
導ＡＩ （１２） （１３）を容器外に導出すること
。 回路は次の各部より成る。 （１） 圧電セラミック （７）にパルス電圧を加え
て変形させ振動板に減衰振動を生じさせる発振器（１４
）。 （Ｕ） セラミック （７）の減衰振動により生起さ
れる電圧を増幅する増幅器（１６）。 （ＩＩＩ） 増幅器（１６）の出力を整流する整流器
（１８）。 （ＩＶ） 整流器（１８）の出力波形を積分する積分
器（１９）。 （Ｖｌ 測定液面に対する積分器（１９）による積分
値を基準液面に対する同様の積分値と比較して測定液面
が基準液面より上にあるか否かを判定する比較器（２１
）。[Claims] A liquid level gauge consisting of a sensing part (3) attached to a container wall and a circuit that cooperates with the sensing part (3), the sensing part (3) having the following configuration. (1) A diaphragm (6) with a piezoelectric ceramic (7) bonded to it that can freely vibrate is attached. (II) A diaphragm (6) that comes into contact with the liquid inside the container when attached to the wall of the container liquid-tightly partitions the inside and outside of the container. (II) Leading out the conductor AI (12) (13) connected to the electrode of the piezoelectric ceramic (7) to the outside of the container. The circuit consists of the following parts. (1) An oscillator (14) that applies a pulse voltage to the piezoelectric ceramic (7) to deform it and generate damped vibration on the diaphragm.
). (U) An amplifier (16) that amplifies the voltage generated by the damped vibration of the ceramic (7). (III) A rectifier (18) that rectifies the output of the amplifier (16). (IV) An integrator (19) that integrates the output waveform of the rectifier (18). (Vl A comparator (21) that compares the integral value of the integrator (19) for the measured liquid level with a similar integral value for the reference liquid level to determine whether the measured liquid level is above the reference liquid level.
).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12969482A JPS5919816A (en) | 1982-07-27 | 1982-07-27 | Level gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12969482A JPS5919816A (en) | 1982-07-27 | 1982-07-27 | Level gauge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5919816A true JPS5919816A (en) | 1984-02-01 |
Family
ID=15015878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12969482A Pending JPS5919816A (en) | 1982-07-27 | 1982-07-27 | Level gauge |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5919816A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04227110A (en) * | 1990-12-28 | 1992-08-17 | Hochiki Corp | Attenuator for catv line amplification |
| JP2006194854A (en) * | 2004-04-19 | 2006-07-27 | Seiko Epson Corp | Liquid detection device and liquid container including the device |
| JP2007147640A (en) * | 2007-01-15 | 2007-06-14 | Seiko Epson Corp | Detection control circuit |
| US7251996B2 (en) | 1999-05-20 | 2007-08-07 | Seiko Epson Corporation | Liquid detecting piezoelectric device, liquid container and mounting module member |
| JP2017534849A (en) * | 2014-09-18 | 2017-11-24 | マシイネンフアブリーク・ラインハウゼン・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Electrical equipment with a casing filled with insulating oil and measuring equipment and method for monitoring the electrical equipment |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5583818A (en) * | 1978-12-20 | 1980-06-24 | Matsushita Electric Ind Co Ltd | Level detector |
| JPS566181A (en) * | 1979-06-27 | 1981-01-22 | Sanyo Electric Co Ltd | Body detector |
| JPS567569A (en) * | 1979-07-02 | 1981-01-26 | Matsushita Electric Ind Co Ltd | Television common receiver |
-
1982
- 1982-07-27 JP JP12969482A patent/JPS5919816A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5583818A (en) * | 1978-12-20 | 1980-06-24 | Matsushita Electric Ind Co Ltd | Level detector |
| JPS566181A (en) * | 1979-06-27 | 1981-01-22 | Sanyo Electric Co Ltd | Body detector |
| JPS567569A (en) * | 1979-07-02 | 1981-01-26 | Matsushita Electric Ind Co Ltd | Television common receiver |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04227110A (en) * | 1990-12-28 | 1992-08-17 | Hochiki Corp | Attenuator for catv line amplification |
| US7251996B2 (en) | 1999-05-20 | 2007-08-07 | Seiko Epson Corporation | Liquid detecting piezoelectric device, liquid container and mounting module member |
| JP2006194854A (en) * | 2004-04-19 | 2006-07-27 | Seiko Epson Corp | Liquid detection device and liquid container including the device |
| JP2007147640A (en) * | 2007-01-15 | 2007-06-14 | Seiko Epson Corp | Detection control circuit |
| JP4656062B2 (en) * | 2007-01-15 | 2011-03-23 | セイコーエプソン株式会社 | Detection control circuit |
| JP2017534849A (en) * | 2014-09-18 | 2017-11-24 | マシイネンフアブリーク・ラインハウゼン・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Electrical equipment with a casing filled with insulating oil and measuring equipment and method for monitoring the electrical equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100582013B1 (en) | Window type probe, plasma monitoring device, and plasma processing device | |
| US4943773A (en) | Magnetostrictive linear displacement transducer having preselected zero crossing detector | |
| US4107994A (en) | Level detector | |
| US8610309B2 (en) | Sensor for switching a pump on and/or off | |
| FI102012B (en) | Vibrator-type level sensor | |
| JPS5883221A (en) | Method and device for detecting liquid in vessel | |
| DE59108274D1 (en) | Device for determining and / or monitoring a predetermined fill level in a container | |
| WO1999014562A1 (en) | Ultrasound sensor for detecting the level of liquids | |
| CA1155197A (en) | Ultra sensitive liquid level detector and method | |
| CA1040455A (en) | Piezoelectric liquid level sensor | |
| JPS5919816A (en) | Level gauge | |
| US5004985A (en) | Method and apparatus for testing the response of a stress wave sensor | |
| US6079266A (en) | Fluid-level measurement by dynamic excitation of a pressure- and fluid-load-sensitive diaphragm | |
| KR950033436A (en) | Liquid level sensor with plunger core | |
| US5943294A (en) | Level detector for fluent material | |
| US5748562A (en) | Level detector for solids | |
| JP2001004431A (en) | Capacity type displacement sensor | |
| JPS58205820A (en) | Liquid level sensor | |
| JPS604819A (en) | Liquid level sensor | |
| JPH01131418A (en) | Method and device for liquid amount detection | |
| US5220826A (en) | Method and apparatus for measuring materials floating on bodies of water | |
| JPS60203831A (en) | Pressure sensor | |
| JP6627831B2 (en) | Liquid level detector | |
| JPS6125024A (en) | Measuring method of liquid level | |
| RU2206069C2 (en) | Attachable gage for measuring liquid level |