JPS607211B2 - Liquid level detection part - Google Patents
Liquid level detection partInfo
- Publication number
- JPS607211B2 JPS607211B2 JP12259680A JP12259680A JPS607211B2 JP S607211 B2 JPS607211 B2 JP S607211B2 JP 12259680 A JP12259680 A JP 12259680A JP 12259680 A JP12259680 A JP 12259680A JP S607211 B2 JPS607211 B2 JP S607211B2
- Authority
- JP
- Japan
- Prior art keywords
- liquid level
- outer cylinder
- liquid
- load cell
- level detection
- 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
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
- G01F23/0038—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 using buoyant probes
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Level Indicators Using A Float (AREA)
Description
【発明の詳細な説明】
本発明は、一部を液体に浸潰し、外筒に作用する、液位
変化に基づく浮力の変化を荷重検出器により検出して液
位を測定する液位検出部に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention provides a liquid level detection unit that measures the liquid level by partially immersing it in liquid and using a load detector to detect changes in buoyancy based on changes in liquid level acting on an outer cylinder. It is related to.
従釆から液体用レベル計としては、例えば浮子式レベル
計、空気圧式レベル計、静電容量式レベル計、超音波レ
ベル計等々各種のものが使用されている。Various types of liquid level meters are used, including, for example, a float type level meter, a pneumatic level meter, a capacitance type level meter, and an ultrasonic level meter.
これらのレベル計にはそれぞれ一長一短があり、用途及
び液体の性状により適宜選択使用されている。然しなが
ら一般に故障が発生し易く、指示が不安定であり、保守
に手間がかかる等の問題点があり、概して高価であると
いう欠点を有している。本発明の目的は、上述の問題点
、欠点を解消し、構造が簡明で高精度の測定値が得られ
、安価な液&検出部を提供することにあり、その内容は
、被測定液の上方から被測定液中にその一部を浸潰して
液位を測定する液位検出部であって、該検出部を液槽に
固定するための取付部を有する基部と、該基部から下方
に垂設した杵体と、該杵体の外側に配置した有底の浮力
検知用外筒と、該外筒の上端部と前記基部とを連結する
蛇腹状の力を伝達しないシール材と、前記外筒の内底部
と前記杵体の下端部との間に介在した荷重検出器とを具
備し、前記外筒に作用する浮力の変化を該荷重検出器に
より検知して液位を測定するようにしたことを特徴とす
るものである。Each of these level meters has advantages and disadvantages, and is selected and used as appropriate depending on the purpose and properties of the liquid. However, they generally have the disadvantages of being prone to breakdowns, unstable instructions, and time-consuming maintenance, and generally being expensive. An object of the present invention is to solve the above-mentioned problems and drawbacks, and to provide a liquid and detection unit that has a simple structure, can obtain highly accurate measurement values, and is inexpensive. A liquid level detection part that measures the liquid level by immersing a part of the part into the liquid to be measured from above, and includes a base having a mounting part for fixing the detection part to a liquid tank, and a part extending downward from the base. a vertically installed punch body, a bottomed buoyancy detection outer cylinder disposed outside the punch body, a bellows-like sealing material that does not transmit force, connecting the upper end of the outer cylinder and the base; A load detector is provided between the inner bottom of the outer cylinder and the lower end of the punch, and the liquid level is measured by detecting changes in buoyancy acting on the outer cylinder with the load detector. It is characterized by the following.
本発明を図示の実施例に基づいて詳細に説明する。The present invention will be explained in detail based on illustrated embodiments.
本発明に係る液位検出部1の実施例は、第1図に示すよ
うに、略円筒状の形状を有し、その下部を被測定液2中
に浸潰し、内部に設置したロードセルからの電気出力信
号を増中回路3に送信し指示回路4により指示するもの
である。As shown in FIG. 1, the embodiment of the liquid level detection unit 1 according to the present invention has a substantially cylindrical shape, the lower part of which is immersed in the liquid to be measured 2, and a load cell installed inside the liquid level detection unit 1 has a substantially cylindrical shape. An electrical output signal is transmitted to the increasing circuit 3 and an instruction circuit 4 instructs it.
この液位検出部1の構造は、第2図に詳細に示している
。液位検出部1の基部5には、例えば液槽6の上部の蓋
部7に取付けるためのフランジから成る取付部8を有し
ており、基部5からその下方に内筒9が華設されており
、この内筒9の外側には底部10を閉塞した浮力検知用
の中空外筒1 1が内筒9と接触することなく配置され
ている。外筒11の底部10と内筒9の下端部とは、例
えばストレィンゲージ式のロードセル12により接続さ
れ、外筒11に作用する浮力をロードセル12によって
検知し得るようになっている。又、外筒11の開放織部
と基部5との間には、外筒11内に液2が侵入しないよ
うに例えば蛇腹状のゴム製シール材13で連結されてお
り、このシール材13によっては外筒11と基部5との
間で力が伝達されないようになっている。ロードセル1
2の電気出力は、内筒9の内部を通り検出部1の外部に
引き出されたりード線14により送信される。従ってこ
の液位検出部1の外筒11の下部を第1図に示すように
被測定液2中に浸潰し、所定の位置に保持すれば、液位
が変動すると外筒11に作用する浮力が変化し、その力
はロードセル12により検知され、液位を測定すること
が可能となる。この原理を数式を用いて説明すると、ロ
ードセル12が外筒11から受ける力をF、外筒11の
断面積をS、外筒11が液2中に浸潰している部分の長
さをh、液体の比重をr、外筒11の重量をWとすれば
F=rSh−VV ・・・
【1)が成立し、外筒11が浸潰している長さh、即ち
液位hは、F,r,Wが既知であることから、‘1}式
を基に、Fを測定することによって求められる。The structure of this liquid level detection section 1 is shown in detail in FIG. The base 5 of the liquid level detection unit 1 has a mounting part 8 consisting of a flange for mounting, for example, to the lid 7 at the top of the liquid tank 6, and an inner cylinder 9 is provided below the base 5. A hollow outer cylinder 11 for buoyancy detection with a closed bottom portion 10 is disposed outside the inner cylinder 9 without contacting the inner cylinder 9. The bottom 10 of the outer cylinder 11 and the lower end of the inner cylinder 9 are connected by, for example, a strain gauge type load cell 12, so that the buoyant force acting on the outer cylinder 11 can be detected by the load cell 12. Further, between the open weave of the outer cylinder 11 and the base 5, a bellows-shaped rubber sealing material 13, for example, is connected to prevent the liquid 2 from entering the outer cylinder 11. No force is transmitted between the outer cylinder 11 and the base 5. Load cell 1
The electrical output of 2 passes through the inside of the inner cylinder 9 and is drawn out to the outside of the detection unit 1 and transmitted by a lead wire 14 . Therefore, if the lower part of the outer cylinder 11 of the liquid level detection unit 1 is immersed in the liquid to be measured 2 and held at a predetermined position as shown in FIG. changes, and the force is detected by the load cell 12, making it possible to measure the liquid level. To explain this principle using a mathematical formula, the force that the load cell 12 receives from the outer cylinder 11 is F, the cross-sectional area of the outer cylinder 11 is S, the length of the part of the outer cylinder 11 submerged in the liquid 2 is h, If the specific gravity of the liquid is r and the weight of the outer cylinder 11 is W, then F=rSh-VV...
[1] is established, and the length h of the submerged outer cylinder 11, that is, the liquid level h, is determined by measuring F based on formula '1} since F, r, and W are known. It is determined by
ロードセル12の電気出力はロードセル12に加わる力
F‘こ比例するので、出力と液位との関係は{1}式で
示す一次式となり、実験の結果とも極めてよく一致する
。。Since the electrical output of the load cell 12 is proportional to the force F' applied to the load cell 12, the relationship between the output and the liquid level is a linear equation shown by the equation {1}, which agrees extremely well with the experimental results. .
ードセル12には、一般には力Fが下方から上方に向く
ために圧縮型とすればよいが、外筒11に作用する浮力
よりも外筒11の重量Wを大とすれば、ロードセル12
に作用する力Fは負となり下向きに作用することになる
ので、ロードセル12を引張り型とすることもできる。
更には荷重検出器としてはロードセル以外に例えばフオ
ースバランス型の差動コイル等を用いてもよい。又、こ
の液位検出部1の取付に当っては、第3図に示すような
取付部8′により液槽6の側壁に直酸取付けるようにし
ても支障はない。内筒9にはリード線14を挿通し易く
する便宜上筒体としたが、必ずしも筒体である必要はな
く、荷重検出器を所定位置に保持するための杵体であれ
ばよい。このように本発明に係る液位検出部1は極めて
簡明な構造で、精度の良い測定値を得ることができる。
然しながら、温度変化等により被測定液の比重がyから
y十△yに変化した場合には、‘1}式からも明らかな
ように△y・Shなる誤差の介入を回避することはでき
ない。従って例えば外筒11内に温度センサを貼付して
液2の熱膨張率を基に温度補償を行なうとか、或いは外
筒11内に例えば油等の液体を充填してその中に温度セ
ンサを浸潰し同様に温度補償を行ない、液位測定値を算
術的に補正することもできる。第4図は前述のような温
度センサによることなく、測定値の比重変化を補償する
ものであり、本発明に係る液位検出部1に並べて比重補
正用の検出部21を設置している。この検出部21は測
定液中に完全に沈設した一定積の基準容積体22が金属
陣等から成る紬径の連結杵23を介して荷重検出部24
内のロードセル(図示を省略)に接続され、基準容積体
22に作用する浮力を検知できるようになっている。特
にこの場合の連結杵23は、液位が変化しても荷重検出
部24内の補正用ロードセルに加わる浮力が殆ど変化し
ないように紬径とすることが必要である。尚、25は基
準容積体22を保護するための保護筒である。この比重
補正用のロードセルからの電気出力は増中回路26を介
して、液位検出部1のロードセル12の出力と共に演算
回路27に入力され、演算回路27で後述する比重の補
正演算がなされ、補正された液位信号が指示回路4に出
力される。この場合の補正用のロードセルに加わる力を
f、基準容積体22の体積をv、連結村23を含めた基
準容積体22の重量をwとすれば、ロードセルに加わる
力fは、f=yV−W “‐{2
}として表わされる。In general, the load cell 12 may be of a compression type since the force F is directed upward from below, but if the weight W of the outer cylinder 11 is larger than the buoyant force acting on the outer cylinder 11, the load cell 12
Since the force F acting on is negative and acts downward, the load cell 12 can also be of a tension type.
Furthermore, as the load detector, for example, a force balance type differential coil or the like may be used in place of the load cell. Further, when mounting the liquid level detecting section 1, there is no problem even if the liquid level detecting section 1 is directly mounted on the side wall of the liquid tank 6 using a mounting section 8' as shown in FIG. Although the inner cylinder 9 has a cylindrical body for convenience of making it easier to insert the lead wire 14, it does not necessarily have to be a cylindrical body, and may be a punch body for holding the load detector in a predetermined position. As described above, the liquid level detection section 1 according to the present invention has an extremely simple structure and can obtain highly accurate measurement values.
However, when the specific gravity of the liquid to be measured changes from y to y+Δy due to a temperature change, etc., it is impossible to avoid the intervention of an error of Δy·Sh, as is clear from the equation '1}. Therefore, for example, a temperature sensor may be attached inside the outer cylinder 11 and temperature compensation may be performed based on the coefficient of thermal expansion of the liquid 2, or a liquid such as oil may be filled in the outer cylinder 11 and the temperature sensor may be immersed therein. Similar to crushing, temperature compensation can also be performed to arithmetically correct the liquid level measurements. FIG. 4 shows a system for compensating for specific gravity changes in measured values without using a temperature sensor as described above, and a detection section 21 for specific gravity correction is installed alongside the liquid level detection section 1 according to the present invention. This detection unit 21 is connected to a load detection unit 24 in which a reference volume 22 of a fixed volume completely submerged in the measuring liquid is passed through a connecting punch 23 with a pongee diameter made of metal or the like.
It is connected to a load cell (not shown) inside, so that the buoyant force acting on the reference volume body 22 can be detected. In particular, the connecting punch 23 in this case needs to have a diameter so that the buoyancy applied to the correction load cell in the load detection section 24 hardly changes even if the liquid level changes. Note that 25 is a protection tube for protecting the reference volume body 22. The electrical output from the load cell for specific gravity correction is inputted to the calculation circuit 27 together with the output of the load cell 12 of the liquid level detection unit 1 via the increase circuit 26, and the calculation circuit 27 performs specific gravity correction calculation, which will be described later. The corrected liquid level signal is output to the indicating circuit 4. In this case, if the force applied to the correction load cell is f, the volume of the reference volume 22 is v, and the weight of the reference volume 22 including the connecting village 23 is w, then the force f applied to the load cell is f=yV -W “-{2
}.
従って{1}及び【2ー式から比重yを消去すると、h
=(v/S)・(F+W)/(f+w).・・【3’
が求められる。Therefore, if we eliminate the specific gravity y from the equations {1} and [2-, we get h
=(v/S)・(F+W)/(f+w). ...[3' is required.
この‘3’式からも明らかなように、F及びfを知るこ
とにより液位hを比重yに関係なく正確に測定すること
が判る。演算回路27には(3’式の演算を実現するた
めの電気回路が組み込まれており、液位検出部1のロー
ドセル12からの力Fと比重補正用の検出部21のロー
ドセルからの力fが入力することにより液位hを演算し
、指示回路5に出力するようになっている。以上説明し
たように本発明に係る液位検出部は可動部分が殆ど全く
なく、浮力を受ける外周はほぼ固定された状態で測定で
きるので故障も極めて少なく保守が容易である。As is clear from this '3' formula, it is understood that by knowing F and f, the liquid level h can be accurately measured regardless of the specific gravity y. The calculation circuit 27 incorporates an electric circuit for realizing the calculation of formula (3'), and calculates the force F from the load cell 12 of the liquid level detection section 1 and the force f from the load cell of the detection section 21 for specific gravity correction. The liquid level h is calculated by inputting the liquid level h, and is output to the indicating circuit 5.As explained above, the liquid level detecting part according to the present invention has almost no moving parts, and the outer periphery that receives the buoyant force is Since measurements can be made in a nearly fixed state, there are very few failures and maintenance is easy.
又測定原理は{1}式により表わされ「極めて簡単な原
理によりなされるので比重の変化以外には誤差の介入も
少なく高精度の測定が可能である。更には比重補正用検
出部を併せて設けることにより比重の変化が生じても正
確な液位を測定できる。In addition, the measurement principle is expressed by the {1} formula, and ``Since it is performed based on an extremely simple principle, there are few errors other than changes in specific gravity, and highly accurate measurement is possible. By providing this, the liquid level can be measured accurately even if the specific gravity changes.
図面は本発明に係る液位検出部の一実施例を示すもので
あり、第1図は測定液中に浸潰した使用状態を示す正面
図、第2図はその縦断面図、第3図は他の取付方法の一
部切欠側面図、第4図は比重補正用検出部を設け、比重
を補正するようにした状態を示す説明図である。
符号1は液位検出部、2は液「 3は増中回路、4は指
示回路「 5は基部、6は液槽、8,8′は取付部、9
は内筒、1川ま底部、11は外筒、12はロードセル、
13はシール材、21は比重補正用検出部、22は基準
容積体、24は荷重検出部である。
第1図
第2図
第3図
第4図The drawings show an embodiment of the liquid level detection section according to the present invention, and FIG. 1 is a front view showing the state of use in which it is immersed in a measuring liquid, FIG. 2 is a longitudinal sectional view thereof, and FIG. 4 is a partially cutaway side view of another mounting method, and FIG. 4 is an explanatory view showing a state in which a detection section for specific gravity correction is provided to correct the specific gravity. 1 is the liquid level detection unit, 2 is the liquid, 3 is the increase circuit, 4 is the indicator circuit, 5 is the base, 6 is the liquid tank, 8 and 8' are the mounting parts, 9
1 is the inner cylinder, 1 is the bottom, 11 is the outer cylinder, 12 is the load cell,
13 is a sealing material, 21 is a detection section for specific gravity correction, 22 is a reference volume body, and 24 is a load detection section. Figure 1 Figure 2 Figure 3 Figure 4
Claims (1)
て液位を測定する液位検出部であつて、該検出部を液槽
に固定するための取付部を有する基部と、該基部から下
方に垂設した杆体と、該杆体の外側に配置した有底の浮
力検知用外筒と、該外筒の上端部と前記基部とを連結す
る蛇腹状の力を伝達しないシール材と、前記外筒の内底
部と前記杆体の下端部との間に介在した荷重検出器とを
具備し、前記外筒に作用する浮力の変化を該荷重検出器
により検知して液位を測定するようにしたことを特徴と
する液位検出部。1. A liquid level detection part that measures the liquid level by immersing a part of the liquid into the liquid to be measured from above, and a base having a mounting part for fixing the detection part to a liquid tank; A rod hanging downward from the base, a bottomed buoyancy detection outer cylinder disposed outside the rod, and a bellows-like sealing material that does not transmit force connecting the upper end of the outer cylinder and the base. and a load detector interposed between the inner bottom of the outer cylinder and the lower end of the rod, and the load detector detects changes in buoyancy acting on the outer cylinder to measure the liquid level. A liquid level detection unit characterized in that:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12259680A JPS607211B2 (en) | 1980-09-04 | 1980-09-04 | Liquid level detection part |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12259680A JPS607211B2 (en) | 1980-09-04 | 1980-09-04 | Liquid level detection part |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5746122A JPS5746122A (en) | 1982-03-16 |
JPS607211B2 true JPS607211B2 (en) | 1985-02-22 |
Family
ID=14839838
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP12259680A Expired JPS607211B2 (en) | 1980-09-04 | 1980-09-04 | Liquid level detection part |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS607211B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT201800005789A1 (en) * | 2018-05-28 | 2019-11-28 | DENSIMETER |
-
1980
- 1980-09-04 JP JP12259680A patent/JPS607211B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS5746122A (en) | 1982-03-16 |
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