JPS60149925A - Negative pressure type liquid level measuring method - Google Patents
Negative pressure type liquid level measuring methodInfo
- Publication number
- JPS60149925A JPS60149925A JP607684A JP607684A JPS60149925A JP S60149925 A JPS60149925 A JP S60149925A JP 607684 A JP607684 A JP 607684A JP 607684 A JP607684 A JP 607684A JP S60149925 A JPS60149925 A JP S60149925A
- Authority
- JP
- Japan
- Prior art keywords
- liquid
- liquid level
- negative pressure
- pressure
- differential pressure
- 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
- G01F23/14—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 measurement of pressure
Landscapes
- Physics & Mathematics (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】
この発明に、圧力式の液位測定方法に係り、特に負圧式
の液位測定方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure type liquid level measuring method, and particularly to a negative pressure type liquid level measuring method.
近年、圧力センサーの進歩にともなって圧力式の液位測
定方法を利用した泡位計が広く使用されているが、圧力
センサーの使用法は、第１図の投込式の場合、第２図の
タンク式の場合、第３図のパージ式の場合など、いずれ
も液上気体圧との正の差圧を測定する方法である。In recent years, with the advancement of pressure sensors, bubble level meters that utilize pressure-based liquid level measurement methods have become widely used. In the case of the tank type shown in Figure 3, and in the case of the purge type shown in Figure 3, both methods measure a positive differential pressure with the gas pressure above the liquid.
すなわち、差圧計の一方に液圧、他方に液上気圧を導入
することにより、
差圧ΔＰは
ΔＰ＝（Ｐｏ＋δＨ１） −Ｐｏ ・・・・・・（１）
、°、ΔＰ＝δＨ１・ ・ ・ ・ ・ ・ ・ ・
・ ・ ・ ・ ・（２）したがって、
Ｈ１＝ΔＰ／δ ・ ・ ・ ・ ・ ・ ・ ・ ・
・ ・ ・（３）であり、液位Ｈは
Ｈ＝ Ｈｏ ＋ Ｈｔ ＝ Ｈｏ＋ΔＰ／δ・・・・・
（４）ここに、
ＨＯ： 基準高
Ｈｌ： 基準高から液面までの高さ
ＰＯ： 液上気体圧
δ ：被測定液体の密度
これらの方法でに、いずれも差圧ΔＰｆｌ正圧であり、
算式である（４）式の誘導は簡明であるが、実施上に次
の欠点がある。すなわち、
（１）投込式およびパージ式の場合、液面下にある基準
高ＨＯを正しく設定し、それを継続的に検定し、維持す
るのが困難である。That is, by introducing liquid pressure to one side of the differential pressure gauge and liquid pressure to the other side, the differential pressure ΔP is calculated as ΔP=(Po+δH1) −Po (1)
, °, ΔP=δH1・ ・ ・ ・ ・ ・ ・ ・
・ ・ ・ ・ ・(2) Therefore, H1=ΔP/δ ・ ・ ・ ・ ・ ・ ・ ・ ・
・ ・ ・(3), and the liquid level H is H = Ho + Ht = Ho + ΔP/δ...
(4) Here, HO: Reference height Hl: Height from the reference height to the liquid level PO: Above-liquid gas pressure δ: Density of the liquid to be measured In both of these methods, the differential pressure ΔPfl is a positive pressure,
Although the derivation of formula (4) is simple, it has the following drawbacks in implementation. That is, (1) In the case of the injection type and the purge type, it is difficult to correctly set the reference height HO below the liquid level, continuously verify it, and maintain it.
（２）投込式およびタンク式の場合、差圧計を液圧のか
かる位置に設定し彦ければならないため、その設置およ
び維持・管理が困難である。(2) In the case of the immersion type and tank type, the differential pressure gauge must be set at a position where liquid pressure is applied, making it difficult to install, maintain, and manage it.
（３）投込式の場合、出力側の電気ケーブルが長くなり
、誘導障害、とくに、野外では誘雷の影響を受け易い。(3) In the case of the immersion type, the electrical cable on the output side is long and is susceptible to inductive disturbances, especially lightning in the field.
（４）パージ式の場合、給気装置の連続運転の安定な継
続に問題がある。(4) In the case of the purge type, there is a problem with stable continuous operation of the air supply device.
この発明の目的は、液位をめるにあたり、被測定液体を
液面上に吸い上げることにより生ずる負圧を測定する方
法をとることによって、上記の欠点をいずれも排除した
ことを特徴とする負圧式液位測定方法を提供しようとす
るものである。An object of the present invention is to eliminate all of the above-mentioned drawbacks by using a method of measuring the negative pressure generated by sucking up the liquid to be measured above the liquid level when measuring the liquid level. The present invention aims to provide a pressure-type liquid level measurement method.
以下、この発明の実施例を添付図面の第４図ないし第６
図に基づいて詳細に説明する。Embodiments of the present invention will be described below with reference to FIGS. 4 to 6 of the accompanying drawings.
This will be explained in detail based on the figures.
第４図は、本発明の負圧式液位測定方法に用いる負圧式
液位針の第１実施例を示し、ここにおいて、１は液面上
に設置された負圧タンクであり、導液パイプ２により被
測定液に連絡している。６．６′ハ貯液タンク４の上下
に設けられた２フのパルプ、５は該パルプ６を介して貯
液タンク４に連結する真空ポンプ、６は負圧タンク１に
連結された差圧計でちる。FIG. 4 shows a first embodiment of a negative pressure liquid level needle used in the negative pressure liquid level measuring method of the present invention, in which 1 is a negative pressure tank installed above the liquid level, and a liquid guiding pipe is shown in FIG. 2 is used to communicate with the liquid to be measured. 6.6'C Two pulps installed above and below the liquid storage tank 4, 5 a vacuum pump connected to the liquid storage tank 4 via the pulp 6, 6 a differential pressure gauge connected to the negative pressure tank 1 Dechiru.
この負圧液位針の始動時ＫＨ１３、・６′の２コのパル
プを開いて真空ポンプ５を動かし、貯液タンク４の中間
まで液を吸い上げた後、３ 、３’の２コのパルプを閉
めれば、液位の変化に従って負圧タンク１の液圧が変化
し、差圧計６によって検知される。なお、負圧タンクＩ
Ｋ気泡が生じた場合は、３′のパルプを開けば貯液タン
ク４に逃がすことができる。When starting this negative pressure liquid level needle, open the two pulps KH13 and 6', move the vacuum pump 5, and suck up the liquid to the middle of the liquid storage tank 4, then open the two pulps KH13 and 6'. When the tank is closed, the liquid pressure in the negative pressure tank 1 changes according to the change in the liquid level, which is detected by the differential pressure gauge 6. In addition, negative pressure tank I
If K bubbles are generated, they can be released into the liquid storage tank 4 by opening the pulp 3'.
この実施例の場合、液位の算式はつぎのとおりである。In this example, the formula for calculating the liquid level is as follows.
すなわち、第４図において、
差圧ΔＰは
ΔＰ＝（Ｐｏ−δＨ１） −Ｐｏ・・・・・・（５）、
゛、ΔＰ−−δＨ１・・・・・・・・・・・・（６）し
たがって、
Ｈｌ ＝−ΔＰ／δ 、 、 、 、 、 、 、 、
、 、 、 （７）となるから、液位Ｈは
Ｈ＝ Ｈｏ −Ｈ１＝ Ｈｏ＋ΔＰ／δ・・、・・（８
）ただし、
ＨＯ： 基準高
Ｈｌ： 液面から基準高までの高さ
ＰＯ： 液上気体圧
δ ：被測定液体の密度
すなわち、基準高ｌ−１ｏ が液面上の差圧計６の位置
にあり、差圧ΔＰが負圧になっているが、算式（８）は
（４）式と全く同形である。That is, in Fig. 4, the differential pressure ΔP is ΔP=(Po−δH1) −Po (5),
゛, ΔP−−δH1・・・・・・・・・・・・(6) Therefore, Hl =−ΔP/δ , , , , , , , ,
, , , (7), so the liquid level H is H = Ho - H1 = Ho + ΔP/δ... (8
) However, HO: Reference height Hl: Height from the liquid level to the reference height PO: Above-liquid gas pressure δ: Density of the liquid to be measured, that is, the reference height l-1o is at the position of the differential pressure gauge 6 above the liquid level. , the differential pressure ΔP is a negative pressure, but the formula (8) is completely the same as the formula (4).
第５図および第６図は負圧液位針の他の実施例を示し、
負圧タンクを省略した形式であって、いずれも貯液タン
ク４ａ、、 ４ｂの断面積と導液パイプ’ｌａ 、 ２
ｂの断面積の比に応じて短周期の圧力変動を消去するこ
とができ、とくに第６図の場合は、貯液タンク４ｂ内の
液面を基準高として一定になるよう制御−すれば、貯液
タンク４ｂ内外の気体の圧力差によって液位を測定する
ことができる。゛なお、この発明の方法では液上気体圧
に対応する液位高の範囲内の液位変化しか測定できない
が、液位が一時的に上昇し、差圧計が液中に没する場合
に対しては、
（１）差圧計として正・負圧型を用いる、（２）差圧計
を密閉容器に収容する、
（３）差圧計の液上気体側の開口部を導管で上部にのば
し、液中に没しないようにする
などによって、液位の測定範囲を差圧計の位置、す々わ
ち、基準高より上に拡大することができる。5 and 6 show other embodiments of the negative pressure level needle,
This type does not include a negative pressure tank, and in both cases, the cross-sectional area of the liquid storage tanks 4a, 4b and the liquid guide pipes are
Short-term pressure fluctuations can be eliminated depending on the ratio of the cross-sectional areas of b, and especially in the case of FIG. 6, if the liquid level in the liquid storage tank 4b is controlled to be constant with reference to the height, The liquid level can be measured based on the pressure difference between the gas inside and outside the liquid storage tank 4b.゛Although the method of this invention can only measure changes in liquid level within the range of liquid level height corresponding to the gas pressure above the liquid, it is possible to measure changes in liquid level only when the liquid level rises temporarily and the differential pressure gauge is submerged in the liquid. (1) Use a positive/negative pressure type as the differential pressure gauge. (2) Store the differential pressure gauge in a sealed container. (3) Extend the opening of the differential pressure gauge on the gas side above the liquid to the top with a conduit and insert it into the liquid. By making sure that the liquid level does not submerge in the water, the measurement range of the liquid level can be expanded to the position of the differential pressure gauge, that is, above the reference height.
この発明によれば、すでに示した投込式・タンク式およ
びパージ式の液位針などが有する欠点をいずれも排除で
きるため、使用する負圧式液位針の設置や維持が容易で
あり、動作の信頼度も高く、また河床変動のはけしい自
然河川や貯水池をにじめ、液面下に差圧計を設置しにく
い構造物や地下水・下水などに対して有効に利用するこ
とができるという効果が得られる。According to this invention, all of the drawbacks of the immersion type, tank type, and purge type liquid level needles mentioned above can be eliminated, so the negative pressure type liquid level needle used is easy to install and maintain, and its operation is easy. It is highly reliable and can be effectively used for natural rivers and reservoirs with rapid river bed fluctuations, structures where it is difficult to install differential pressure gauges below the liquid level, groundwater, sewage, etc. Effects can be obtained.
添付図面の第１図ないし第３図は、従来の圧力式液位測
定方法を用いた液位針の断面図を示し、第１図は投込式
、第２図はタンク式、第３図はパージ式である。また添
付図面の第４図ないし第６図は、本発明の負圧式液位測
定方法を用いた液位針の断面図を示し、第４図は第１実
施例、第５図および第６図は他の実施例である。
１・・・負圧タンク、２．２ａ、２ｂ・・・導液パイプ
、３．３’、３ａ、３ｂ、、、バルブ、
４ 、４ａ 、 ４ｂ・・・貯液タンク、５ 、５ａ
、 ５ｂ・・・真空ポンプ、６ 、６ａ 、 ６ｂ・・
・差圧計
特許出願人 株式会社水管理工学研究所定１図
４ − 四
（Figures 1 to 3 of the accompanying drawings show cross-sectional views of liquid level needles using conventional pressure-type liquid level measurement methods, with Figure 1 being an immersion type needle, Figure 2 being a tank type needle, and Figure 3 being a tank type needle. is a purge type. Further, FIGS. 4 to 6 of the accompanying drawings show cross-sectional views of a liquid level needle using the negative pressure type liquid level measuring method of the present invention, and FIG. 4 shows the first embodiment, and FIGS. is another example. 1... Negative pressure tank, 2.2a, 2b... Liquid guide pipe, 3.3', 3a, 3b,... Valve, 4, 4a, 4b... Liquid storage tank, 5, 5a
, 5b...vacuum pump, 6, 6a, 6b...
・Differential pressure gauge patent applicant Water Management Engineering Research Institute Co., Ltd. 1 Figure 4-4 (
Claims (1)
に対する負圧を測定することにより、液位をめることを
特徴とする負圧式液位測定方法。A negative pressure type liquid level measurement method characterized in that the liquid level is determined by measuring the negative pressure of the liquid sucked up onto the surface of the liquid to be measured using a conduit relative to the gas pressure above the liquid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP607684A JPS60149925A (en) | 1984-01-17 | 1984-01-17 | Negative pressure type liquid level measuring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP607684A JPS60149925A (en) | 1984-01-17 | 1984-01-17 | Negative pressure type liquid level measuring method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60149925A true JPS60149925A (en) | 1985-08-07 |
Family
ID=11628476
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP607684A Pending JPS60149925A (en) | 1984-01-17 | 1984-01-17 | Negative pressure type liquid level measuring method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60149925A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0275532U (en) * | 1988-11-26 | 1990-06-08 | ||
| GB2464106A (en) * | 2008-10-02 | 2010-04-07 | Stephen Thomas Currah | A means for measuring the volume of liquid in a storage tank, and for detecting losses |
| JP2014234681A (en) * | 2013-06-04 | 2014-12-15 | 株式会社大林組 | Ground-water level lowering system |
| CN104949730A (en) * | 2014-03-27 | 2015-09-30 | 大唐安阳发电厂 | Temperature compensation type boiler drum liquid level meter |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS499273A (en) * | 1972-05-13 | 1974-01-26 |
-
1984
- 1984-01-17 JP JP607684A patent/JPS60149925A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS499273A (en) * | 1972-05-13 | 1974-01-26 |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0275532U (en) * | 1988-11-26 | 1990-06-08 | ||
| GB2464106A (en) * | 2008-10-02 | 2010-04-07 | Stephen Thomas Currah | A means for measuring the volume of liquid in a storage tank, and for detecting losses |
| JP2014234681A (en) * | 2013-06-04 | 2014-12-15 | 株式会社大林組 | Ground-water level lowering system |
| CN104949730A (en) * | 2014-03-27 | 2015-09-30 | 大唐安阳发电厂 | Temperature compensation type boiler drum liquid level meter |
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