JPS63171322A - Flow velocity measuring instrument - Google Patents
Flow velocity measuring instrumentInfo
- Publication number
- JPS63171322A JPS63171322A JP188987A JP188987A JPS63171322A JP S63171322 A JPS63171322 A JP S63171322A JP 188987 A JP188987 A JP 188987A JP 188987 A JP188987 A JP 188987A JP S63171322 A JPS63171322 A JP S63171322A
- Authority
- JP
- Japan
- Prior art keywords
- fluid
- measured
- flow velocity
- negative pressure
- angle
- 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
- 239000012530 fluid Substances 0.000 claims abstract description 79
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 10
- 238000001514 detection method Methods 0.000 claims description 87
- 239000002131 composite material Substances 0.000 abstract description 11
- 238000010586 diagram Methods 0.000 description 10
- 239000000428 dust Substances 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 238000006073 displacement reaction Methods 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Measuring Volume Flow (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は流速測定装置に関するものであり、特に、巨大
なパイプ中を流れる塵埃等を含む流体の流速を測定する
に適した流速測定装置に関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a flow velocity measuring device, and particularly to a flow velocity measuring device suitable for measuring the flow velocity of a fluid containing dust and the like flowing through a huge pipe. It is something.
流体の流速あるいは流量を測定する流速あるいは流量測
定装置として、種々の原理に基づくものが提案され実用
化されてきている。その−例として、オリフィス式の流
量測定装置、ピトー管式流速測定装置、熱線流速計、を
磁流速計等が挙げられる。2. Description of the Related Art As flow rate or flow rate measuring devices for measuring the flow rate or flow rate of a fluid, devices based on various principles have been proposed and put into practical use. Examples thereof include an orifice type flow rate measuring device, a pitot tube type flow rate measuring device, a hot wire current meter, a magnetic current meter, and the like.
しかし、たとえば製鉄工場等に設置されている内径が5
〜10mにも及ぶような巨大な送風管や燃焼廃ガス管を
流れる粉塵を多く含んだ空気等の流速あるいは流量を測
定するとなると、適切なものが無いのが現状である。However, for example, the inner diameter of the equipment installed in steel factories, etc. is 5.
Currently, there is no suitable method for measuring the flow velocity or flow rate of air containing a large amount of dust flowing through huge blast pipes or combustion waste gas pipes that can extend up to 10 m.
オリフィス式の流量測定装置は、巨大な口径のパイプに
取り付けられるオリフィス自体が現実的でない上に、パ
イプ中の粉塵が付着してしまい十分な測定精度が得られ
ない。In an orifice-type flow rate measuring device, the orifice itself is not practical to be attached to a pipe of a huge diameter, and dust in the pipe adheres to it, making it difficult to obtain sufficient measurement accuracy.
ピトー管式の流速測定装置では、パイプの口径が大きい
ことは問題とならないが、ピトー管の目づまりが問題と
なる。すなわち、流れの全圧を測定すべく流れに向かっ
て開口するピトー管の全圧孔が燃焼廃ガス等の被測定流
体中に含まれる粉塵等によって塞がれてしまうのである
。In a pitot tube type flow rate measuring device, the large diameter of the pipe is not a problem, but clogging of the pitot tube is a problem. That is, the total pressure hole of the pitot tube, which opens toward the flow to measure the total pressure of the flow, becomes blocked by dust and the like contained in the fluid to be measured, such as combustion waste gas.
ジュール熱によって加熱したサーミスタ等を被測定流体
によって冷却し、冷却の程度に基づいて流速を測定する
熱線流速計も、流体中の埃等の付着による経時変化が大
きいという欠点を有する。Hot wire anemometers, which cool a thermistor or the like heated by Joule heat with a fluid to be measured and measure the flow velocity based on the degree of cooling, also have the disadvantage of large changes over time due to adhesion of dust, etc. in the fluid.
そして、この熱線流速計は、センサ要素である金属フィ
ラメントまたはサーミスタを直接流体中に曝すため非常
に壊れやすいという欠点も有する。This hot wire anemometer also has the disadvantage that it is very fragile because the sensor element, which is a metal filament or a thermistor, is directly exposed to the fluid.
また、ファラデーの電磁誘導の法則を利用する電磁流量
計は、流体が導電性であれば高粘度であっても、あるい
は微粒子が混在していても測定が可能であるが、被測定
流体が導電性流体であるものに限られるため、例えば空
気のような非導電性流体の流量は測定することができな
い。Furthermore, electromagnetic flowmeters that utilize Faraday's law of electromagnetic induction can measure even if the fluid is highly viscous or contains fine particles, as long as the fluid is conductive. Since the method is limited to electrically conductive fluids, it is not possible to measure the flow rate of non-conductive fluids such as air.
本発明の流速測定装置は上記問題点に鑑みてなされたも
のであり、臨界負圧角度(被測定流体の上流を基準とす
る角度であって被測定流体から負圧力を受け得る最小角
度)よりも大きく、安定最小角度(被測定流体の上流を
基準とする角度であって被測定流体から受ける負圧力が
角度に係わらずほぼ一定となる最小角度)よりも小さい
仰角をもって被測定流体中に露出する第1の開口と、臨
界負圧角度より大きく、安定最小角度より小さい仰角を
もち、被測定流体の基本的な流れの方向を基準にして第
1の開口と反対側において被測定流体中に露出する第2
の開口とを有する第1の流速検出管と、安定最小角度よ
りも大きい仰角もって被測定流体中に露出する第3の開
口を有する第2の流速検出管と、第1の流速検出管内に
生じた負圧と第2の流速検出管内に生じた負圧の差から
被測定流体の流速を算出する演算手段とを備えたもので
ある。The flow rate measuring device of the present invention has been developed in view of the above-mentioned problems. exposed to the measured fluid at an elevation angle that is smaller than the minimum stable angle (the minimum angle with respect to the upstream of the measured fluid at which the negative pressure received from the measured fluid remains approximately constant regardless of the angle). a first opening having an elevation angle greater than the critical negative pressure angle and less than the minimum stable angle; 2nd exposed
a second flow velocity detection tube having a third opening exposed in the fluid to be measured with an elevation angle greater than the minimum stable angle; The flow rate of the fluid to be measured is calculated from the difference between the negative pressure generated in the second flow rate detection tube and the negative pressure generated in the second flow rate detection tube.
また、臨界負圧角度よりも大きく、最大負圧角度(被測
定流体の上流を基準とする角度であって被測定流体から
受ける負圧力が最大となる角度)よりも小さい仰角をも
って被測定流体中に露出する第1の開口と、最大負圧角
度よりも大きく、安定最小角度よりも小さい仰角をもっ
て被測定流体中に露出する第2の開口とを有する第1の
流速検出管と、安定最小角度よりも大きい仰角もって被
測定流体中に露出する第3の開口を有する第2の流速検
出管と、第1の流速検出管内に生じた負圧と第2の流速
検出管内に生じた負圧の差から被測定流体の流速を算出
する演算手段とを備えたものである。In addition, the angle of elevation in the fluid to be measured is larger than the critical negative pressure angle and smaller than the maximum negative pressure angle (the angle with respect to the upstream of the fluid to be measured at which the negative pressure received from the fluid to be measured is the maximum). a first opening exposed into the fluid to be measured with an elevation angle larger than the maximum negative pressure angle and smaller than the stable minimum angle; a second flow velocity detection tube having a third opening exposed in the fluid to be measured with an elevation angle greater than and calculation means for calculating the flow velocity of the fluid to be measured from the difference.
被測定流体の流れによって第1の流速検出管の内部およ
び第2の流速検出管の内部にそれぞれ異なる値の負圧状
態が形成され、しかも、その負圧差は被測定流体の流速
に応じて変化するので、負圧差から被測定流体の流速を
知ることができる。Due to the flow of the fluid to be measured, negative pressure states with different values are formed inside the first flow velocity detection tube and inside the second flow velocity detection tube, and the negative pressure difference changes depending on the flow velocity of the fluid to be measured. Therefore, the flow velocity of the fluid to be measured can be determined from the negative pressure difference.
また、被測定流体の流れに揺れが生じた場合であっても
、第1の開口における負圧力の変化と第2の開口におけ
る負圧力の変化は互いに相反するので、結果として第1
の流速検出管内の内部負圧力には変化が生じない、一方
、第3の開口における負圧力は、被測定流体の流れの揺
れに対し、元来はとんど変化しない、そのため、被測定
流体の流れの揺れによる測定誤差がほとんどない。Furthermore, even if fluctuations occur in the flow of the fluid to be measured, the changes in the negative pressure at the first opening and the changes in the negative pressure at the second opening contradict each other.
There is no change in the internal negative pressure inside the flow rate detection tube.On the other hand, the negative pressure at the third opening does not change much due to fluctuations in the flow of the fluid to be measured. There is almost no measurement error due to flow fluctuations.
以下、実施例と共に本発明の詳細な説明する。 Hereinafter, the present invention will be described in detail along with examples.
第1図は本発明の一実施例を示す概略構成図である。断
面表示されているパイプ1は例えばダクトのようなもの
であり、内部を被測定流体である塵埃を含む空気が白抜
き表示した矢印の方向に流れている。パイプ1内には、
第1の流速検出管2および第2の流速検出管3からなる
複合流速検出管4が被測定流体の流れを横切るように配
置されている。第2図は、複合流速検出管4の全体を示
す斜視図であり、第3図はそのm−m ’断面図である
。FIG. 1 is a schematic diagram showing an embodiment of the present invention. The pipe 1 shown in cross section is, for example, a duct, through which air containing dust, which is the fluid to be measured, flows in the direction of the arrow shown in outline. Inside pipe 1,
A composite flow velocity detection tube 4 consisting of a first flow velocity detection tube 2 and a second flow velocity detection tube 3 is arranged to cross the flow of the fluid to be measured. FIG. 2 is a perspective view showing the entire composite flow velocity detection tube 4, and FIG. 3 is a cross-sectional view taken along the line mm'.
第1の流速検出管2には、被測定流体の上流を基準にし
て時計方向にθl (本実施例では76°)の仰角をも
つ開口5および反時計方向にθ2 (=θ1)の仰角を
持つ開口6がそれぞれ4個ずつほぼ等間隔に設けられて
いる。第2の流速検出管3には、被測定流体の上流を基
準にして1800の仰角を持った、すなわち下流の方向
を向いた開ロアが4個設けられている。The first flow velocity detection tube 2 has an opening 5 having an elevation angle of θl (76° in this example) in the clockwise direction and an elevation angle of θ2 (=θ1) in the counterclockwise direction with respect to the upstream of the fluid to be measured. Four openings 6 each are provided at approximately equal intervals. The second flow velocity detection tube 3 is provided with four open lowers having an elevation angle of 1800 with respect to the upstream of the fluid to be measured, that is, facing in the downstream direction.
第1の流速検出管2および第2の流速検出管3の先端は
いずれも閉じており、末端にはそれぞれ接継1−ト16
.17が形成されている。接継ポー)16.17は、パ
イプ1の外側に突出しており、それぞれ図示省略したチ
ューブによって一点鎖線で示すように圧力計9.10に
接続されている。The tips of the first flow rate detection tube 2 and the second flow rate detection tube 3 are both closed, and each end has a connecting port 16.
.. 17 is formed. The connecting ports 16 and 17 protrude outside the pipe 1, and are connected to pressure gauges 9 and 10 by tubes (not shown), respectively, as shown by dashed lines.
圧力計9および10はそれぞれ第1の流速検出管2およ
び第2の流速検出管3の内部圧力を検出する手段であり
、その出力端子はそれぞれ演算手段11の入力端子に接
続されている。演算手段11は圧力計9および10の出
力から第1の流速検出管2内の負圧力と第2の流速検出
管3内の負圧力との差を算出するものであり、圧力計9
.10と共に負圧差検出手段8を構成している。The pressure gauges 9 and 10 are means for detecting the internal pressure of the first flow rate detection tube 2 and the second flow rate detection tube 3, respectively, and their output terminals are connected to the input terminal of the calculation means 11, respectively. The calculation means 11 calculates the difference between the negative pressure in the first flow rate detection tube 2 and the negative pressure in the second flow rate detection tube 3 from the outputs of the pressure gauges 9 and 10.
.. Together with 10, it constitutes negative pressure difference detection means 8.
負圧差検出手段8の出力端子すなわち演算手段11の出
力端子は演算手段12の入力端子に接続されている。演
算手段12は、予め測定により求められた特性曲線に従
って負圧差検出手段8の出力に対応する被測定流体の流
速を算出する。The output terminal of the negative pressure difference detection means 8, that is, the output terminal of the calculation means 11 is connected to the input terminal of the calculation means 12. The calculation means 12 calculates the flow velocity of the fluid to be measured corresponding to the output of the negative pressure difference detection means 8 according to a characteristic curve determined in advance by measurement.
なお、このようにして求められた被測定流体の流速は、
表示手段により表示されたり、制御系に対する入力信号
となったりする。The flow velocity of the fluid to be measured determined in this way is
It is displayed on a display means or serves as an input signal to a control system.
ここで、本発明の動作原理すなわち第1の流速検出管2
内に生じる負圧力と第2の流速検出管3内に生じる負圧
力の差から被測定流体の流速をいかにして知り得るのか
を説明する。Here, the operating principle of the present invention, that is, the first flow velocity detection tube 2
We will explain how the flow velocity of the fluid to be measured can be determined from the difference between the negative pressure produced within the second flow velocity detection tube 3 and the negative pressure produced within the second flow velocity detection tube 3.
まず、第4図に実験装置の概要を示す。実験はファンモ
ータ50とこれに接続する空気用配管51で空気の流れ
を作り、この空気配管51中(A点の部分)に挿入され
る流速検出管の内部圧力をマノメータ52で測定するこ
とにより行われた。First, Fig. 4 shows an outline of the experimental apparatus. The experiment was conducted by creating an air flow with a fan motor 50 and an air pipe 51 connected to it, and measuring the internal pressure of a flow velocity detection tube inserted into the air pipe 51 (at point A) with a manometer 52. It was conducted.
空気用配管51内の空気の流速は、ファンモータ50に
供給する電源電圧をスライダック53で調整することに
より変化させることができ、空気の流速は市販の流速計
で別途測定できるようにしである。The flow velocity of the air in the air pipe 51 can be changed by adjusting the power supply voltage supplied to the fan motor 50 using the slider 53, and the air flow velocity can be measured separately using a commercially available current meter.
この実験で用いた流速検出管は第5図に示すように、先
端の封止された円管54の表面に直径1酊若しくは2H
の開口55a〜55eが等間隔で複数個形成されている
ものである。この管54は空気用配管51の管壁に垂直
に且っ回動自在に挿入されており、開口55a〜55e
の向きを空気の流れ(白抜きの矢印)に対して自由に変
えることができるようになっている。開口55a〜55
eが空気の流れに対する角度、すなわち流れの上流を0
度としたときの角度を仰角θ (但し、o″≦θ≦18
0°)と定義する。すなわち空気の流れに対して完全に
背を向けているときが180度となる。As shown in FIG. 5, the flow rate detection tube used in this experiment has a diameter of 1 mm or 2 mm on the surface of a circular tube 54 with a sealed tip.
A plurality of openings 55a to 55e are formed at equal intervals. This pipe 54 is vertically and rotatably inserted into the pipe wall of the air pipe 51, and has openings 55a to 55e.
The direction of the air can be freely changed with respect to the air flow (white arrow). Openings 55a-55
e is the angle to the air flow, i.e. the upstream of the flow is 0
The angle in degrees is the elevation angle θ (however, o″≦θ≦18
0°). In other words, when you are completely facing away from the airflow, it is 180 degrees.
かかる実験装置において、空気用配管51内の空気の流
速を一定にして仰角θを変化させたところ、第6図に示
すような結果が得られた。第6図は流速検出管54にお
ける内部圧力の仰角θに対する依存性を示すものであり
、共に横軸は仰角θを示し、縦軸は内部空気圧のゲージ
圧力であり単位は水柱(mAq)である。同図において
、0点でプロットされている特性Aは開口55aから5
5eの直径がIRの場合であり、Δ点でプロットされて
いる特性Bはその直径が2鶴の場合を示している。また
、第7図は、第6図の仰角θ=45゜〜90″付近を拡
大したものである。なお、この実験では空気の流速を5
m / sにセットして行われた。In this experimental device, when the elevation angle θ was varied while keeping the flow velocity of the air in the air pipe 51 constant, results as shown in FIG. 6 were obtained. FIG. 6 shows the dependence of the internal pressure in the flow rate detection tube 54 on the elevation angle θ, and in both cases, the horizontal axis shows the elevation angle θ, and the vertical axis shows the gauge pressure of the internal air pressure, and the unit is water column (mAq). . In the same figure, the characteristic A plotted at the 0 point is 5 from the opening 55a.
This is the case where the diameter of 5e is IR, and the characteristic B plotted at the point Δ is the case where the diameter is 2 cranes. In addition, Fig. 7 is an enlarged view of the elevation angle θ = 45° to 90'' in Fig. 6. In this experiment, the air flow velocity was set to 5
It was set at m/s.
この実験データから、管54の内部空気圧は仰角θが所
定の値よりも太き(なると負になると共に、この内部圧
力が仰角θによって変化することが明らかとなった。例
えば第6図の実験データでみるならば、内部圧力が負に
なり始める仰角θ(以下、臨界負圧角度という)は開口
径1mの場合で約45″付近、開口径2amの場合で約
54″付近であり、最大の負圧を示す仰角θ(以下、最
大負圧角度という)は開口径に係わらず約70度である
。また、内部圧力が角度によらずほぼ安定し始める仰角
θ(以下、安定最小角度という)は、開口径に係わらず
約80°である。なお、これらの臨界負圧角度、最大負
圧角度あるいは安定最小角度の値は、管54や開口55
の形状・個数、レイノルズ数、あるいは流れの前方に設
けられる整流板の有無等によって変化するのであくまで
一例である。以上の実験から、被測定流体の流れに対す
る仰角に応じて異なる負圧が生じることが明らかとなっ
た。From this experimental data, it has become clear that the internal air pressure of the tube 54 becomes negative when the elevation angle θ is greater than a predetermined value (and that this internal pressure changes depending on the elevation angle θ. For example, the experiment shown in FIG. 6 Looking at the data, the elevation angle θ (hereinafter referred to as the critical negative pressure angle) at which the internal pressure starts to become negative is around 45″ for an opening diameter of 1 m, and around 54″ for an opening diameter of 2 am, which is the maximum. The elevation angle θ indicating the negative pressure (hereinafter referred to as the maximum negative pressure angle) is approximately 70 degrees regardless of the opening diameter. ) is approximately 80° regardless of the opening diameter.The values of these critical negative pressure angles, maximum negative pressure angles, or stable minimum angles are approximately 80° regardless of the opening diameter.
This is just an example, as it varies depending on the shape and number of flow plates, Reynolds number, presence or absence of a rectifying plate provided in front of the flow, etc. From the above experiments, it has become clear that different negative pressures are generated depending on the elevation angle with respect to the flow of the fluid to be measured.
そして、このような基本的な現象に基づいてさらに実験
を重ねたところ、かかる負圧力は被測定流体の流速の増
大に応じて増加し、特に負圧力の異なる2点における負
圧力差が被測定流体の流速の増大に応じて増加すること
が確認された。たとえば最大負圧角度(70°前後)に
おける負圧力と安定最小角度(80″前後)における負
圧力との差は、被測定流体の流速の増大と共に増大する
ことになる。Further experiments based on this basic phenomenon revealed that the negative pressure increases as the flow rate of the fluid being measured increases, and in particular, the negative pressure difference between two points with different negative pressures increases. It was confirmed that it increases as the fluid flow rate increases. For example, the difference between the negative pressure at the maximum negative pressure angle (around 70 degrees) and the negative pressure at the minimum stable angle (around 80'') increases as the flow rate of the fluid to be measured increases.
第1図〜第3図に示す実施例はこの原理を利用したもの
であり、第1の流速検出管2に76″という仰角をもつ
開口5.6を上下にそれぞれ設け、第2の流速検出管3
に180°という仰角をもつ開ロアを設け、負圧差検出
手段8および演算手段12において、予め求められてい
る特性曲線に流速検出管2,3で検出した負圧差を適用
し、被測定流体の流速を算出するものである。The embodiment shown in FIGS. 1 to 3 utilizes this principle, and the first flow velocity detection tube 2 is provided with openings 5.6 at the top and bottom with an elevation angle of 76", and the second flow velocity detection tube 3
An open lower part with an elevation angle of 180° is provided, and the negative pressure difference detected by the flow rate detection tubes 2 and 3 is applied to the characteristic curve determined in advance in the negative pressure difference detection means 8 and the calculation means 12, and the This is to calculate the flow velocity.
ところで、第1の流速検出管2の開口5,6は、パイプ
1によって規制される被測定流体の基本的な流れの方向
を基準にして互いに反対側になるように設けられている
。つまり、第1図〜第3図において開口5は上側に開口
6は下側になるように設けられている。一方、第2の流
速検出管3の開ロアは安定最小角度よりも逼かに大きい
仰角をもって設けられている。Incidentally, the openings 5 and 6 of the first flow velocity detection tube 2 are provided so as to be opposite to each other with respect to the basic flow direction of the fluid to be measured regulated by the pipe 1. That is, in FIGS. 1 to 3, the opening 5 is provided on the upper side and the opening 6 is provided on the lower side. On the other hand, the open lower portion of the second flow velocity detection tube 3 is provided with an elevation angle much larger than the minimum stable angle.
このような仰角の設定は、被測定流体の流れに揺れが生
じても、十分に安定した流速測定ができることを可能に
している。Setting the elevation angle in this manner makes it possible to perform sufficiently stable flow velocity measurements even when fluctuations occur in the flow of the fluid to be measured.
たとえば、被測定流体の流速が一定のままで、その流れ
の方向のみが第3図に示す基本的な流れの方向1に対し
てα0変位して方向2となったとする。この角度変位は
、第1の流速検出管2の上側に穿設された開口5の仰角
を実質的にα°小さくし、下側に穿設された開口6の仰
角を実質的にα0大きくしている。したがって、第8図
の特性図に示すように、開口5に関しては負圧力が増大
し、開口6に関しては負圧力が減少する。そのため、被
測定流体の流れの角度変位α0に対する開口5,6の負
圧力の変化分は互いに相殺し合い、結果として、第1の
流速検出管2の内部負圧力は、流れ1のときとほぼ等し
くなる。For example, suppose that the flow velocity of the fluid to be measured remains constant, but only the flow direction is shifted by α0 from the basic flow direction 1 shown in FIG. 3 to become direction 2. This angular displacement substantially reduces the elevation angle of the opening 5 formed on the upper side of the first flow velocity detection tube 2 by α°, and substantially increases the elevation angle of the opening 6 formed on the lower side by α0. ing. Therefore, as shown in the characteristic diagram of FIG. 8, the negative pressure with respect to the opening 5 increases, and the negative pressure with respect to the opening 6 decreases. Therefore, the changes in the negative pressure of the openings 5 and 6 with respect to the angular displacement α0 of the flow of the fluid to be measured cancel each other out, and as a result, the internal negative pressure of the first flow velocity detection tube 2 is almost equal to that for flow 1. Become.
一方、第2の流速検出管3の開ロアは、被測定流体の角
度変位α0に対してその仰角が実質的にα0小さくなる
。しかし、第6図から明らかなように、安定最小角度よ
り大きき角度では仰角が変化しても負圧力はほとんど変
わらないため、第2の流速検出管3の内部負圧力も流れ
1のときとほぼ等しい。On the other hand, the open lower portion of the second flow velocity detection tube 3 has an elevation angle α0 substantially smaller than the angular displacement α0 of the fluid to be measured. However, as is clear from FIG. 6, at angles larger than the minimum stable angle, the negative pressure hardly changes even if the elevation angle changes, so the internal negative pressure of the second flow velocity detection tube 3 also remains the same as when flow 1. Almost equal.
したがって、被測定流体の流れの方向に多少の角度変位
α0があっても、第1の流速検出管2と第2の流速検出
管3における負圧差はほとんど変化しない。Therefore, even if there is some angular displacement α0 in the flow direction of the fluid to be measured, the negative pressure difference between the first flow velocity detection tube 2 and the second flow velocity detection tube 3 hardly changes.
なお、本実施例では、第1の流速検出管2の開口5,6
を、最大負圧角度(約70°)から安定最小角度(約8
0°)の間の角度としたが、臨界負圧角度よりも大きく
、安定最小角度よりも小さければ、最大負圧角度より小
さくてもよい。たとえば、開口5.6の仰角を基本の流
れ1に対して65″とすると、第7図の特性図かられか
るように、開口5の負圧力が増加し、開口6の負圧力が
減少することになり、増加・減少の方向が本実施例と反
対となるが結果として第1の流速検出管2の負圧力は、
本実施例と同様はとんど変化しない。Note that in this embodiment, the openings 5 and 6 of the first flow velocity detection tube 2
from the maximum negative pressure angle (approximately 70°) to the stable minimum angle (approximately 8
0°), but the angle may be smaller than the maximum negative pressure angle as long as it is larger than the critical negative pressure angle and smaller than the minimum stable angle. For example, if the elevation angle of the opening 5.6 is set to 65'' with respect to the basic flow 1, the negative pressure at the opening 5 will increase and the negative pressure at the opening 6 will decrease, as seen from the characteristic diagram in Figure 7. Therefore, although the direction of increase and decrease is opposite to that in this embodiment, the negative pressure in the first flow velocity detection tube 2 is as follows.
Similar to this embodiment, there is almost no change.
また、本実施例では、開口5.6は、その向きが被測定
流体の流れの方向を基準にして互いに反対を向いている
ものの、絶対値は共に76″で等しい。しかし、必ずし
も絶対値を等しくする必要はない。たとえば、開口5が
74°で開口6が78″であっても、角度変位α0に対
して開口5では負圧力が増加し、開口6では負圧力が減
少するので、負圧力は安定する。In addition, in this embodiment, although the openings 5.6 are oriented in opposite directions with respect to the flow direction of the fluid to be measured, their absolute values are both 76'' and the same. However, the absolute values are not necessarily the same. They do not need to be equal. For example, even if the opening 5 is 74° and the opening 6 is 78", the negative pressure increases at the opening 5 and decreases at the opening 6 with respect to the angular displacement α0. The pressure becomes stable.
また、本実施例の負圧差検出手段8は、流速検出管2,
3のそれぞれの負圧力を検出する圧力計9.10および
その圧力差を算出する演算手段11から構成されている
が、第9図に示すような連通管18および微小流量検出
手段19によって構成することもできる。Further, the negative pressure difference detection means 8 of this embodiment includes the flow velocity detection tube 2,
3, and a calculation means 11 for calculating the pressure difference between the pressure gauges 9 and 10, and a communication pipe 18 and a minute flow rate detection means 19 as shown in FIG. You can also do that.
すなわち、第1の流速検出管2に生じる負圧現象と第2
の流速検出管3に生じる負圧現象との相違から連通管1
8に流れを生じさせることができ、連通管18を流れる
流体の速度または流量から負圧差を知ることができるの
である。この微小流量検出手段19の出力は演算手段1
2に供給されて被測定流体の流速に変換される。なお、
微小流量検出手段19の出力と被測定流体の流速との関
係が予め測定により求められており、この関係が校正曲
線として演算手段12に書き込まれている。That is, the negative pressure phenomenon occurring in the first flow velocity detection tube 2 and the second
Due to the difference between the negative pressure phenomenon that occurs in the flow rate detection tube 3, the communication tube 1
8, and the negative pressure difference can be determined from the velocity or flow rate of the fluid flowing through the communication pipe 18. The output of this minute flow rate detection means 19 is
2 and is converted into the flow velocity of the fluid to be measured. In addition,
The relationship between the output of the minute flow rate detection means 19 and the flow velocity of the fluid to be measured is determined in advance by measurement, and this relationship is written in the calculation means 12 as a calibration curve.
第10図は、微小流量検出手段19として好適なものの
一例を示すものである。この微小流量検出手段19は、
半導体の異方性エツチング技術に基づいたブリッジ構造
によって熱式の風速検出器を構成するものであって、検
出部が半導体基板と熱的に分離されていることから極め
て微少な流速も検出できる点に特徴がある。同図(a)
は斜視図、(b)はそのB−B断面図である。破線で囲
まれた領域21の真下には、左右の開口22.23を連
通ずる貫通孔24が形成されている。すなわち、領域2
1はブリッジ状に半導体基台25がら空間的に離隔して
おり、結果的に領域21を半導体基台25から熱的に絶
縁している。この領域21の表面には、同図(c)に概
略構成を示すように薄膜のヒータエレメント26とそれ
を挟む薄膜の測温抵抗ニレメン)27.28が形成され
ている。同図(C)において矢印りが示す方向に流体が
移動すると、上流側の測温抵抗エレメント27は冷却さ
れ、ヒータエレメント26によって暖められた流体も同
方向に移動するため測温抵抗エレメント28が暖められ
る。そのため、測温抵抗エレメント27と28との出力
に差が生じ、この出力差から同図(d)に示すように流
体の流速が検出できる。FIG. 10 shows an example suitable as the minute flow rate detection means 19. This minute flow rate detection means 19 is
The thermal wind speed detector is constructed using a bridge structure based on semiconductor anisotropic etching technology, and since the detection part is thermally separated from the semiconductor substrate, it is possible to detect even extremely small flow speeds. There are characteristics. Figure (a)
is a perspective view, and (b) is a BB sectional view thereof. A through hole 24 that communicates the left and right openings 22 and 23 is formed directly below the region 21 surrounded by the broken line. That is, area 2
1 is spatially separated from the semiconductor base 25 in the form of a bridge, and as a result, the region 21 is thermally insulated from the semiconductor base 25. On the surface of this region 21, a thin film heater element 26 and thin film temperature measuring resistors 27 and 28 sandwiching it are formed, as schematically shown in FIG. 2(c). When the fluid moves in the direction indicated by the arrow in FIG. It's warm. Therefore, a difference occurs between the outputs of the temperature measuring resistance elements 27 and 28, and from this output difference, the flow velocity of the fluid can be detected as shown in FIG. 2(d).
つぎに、本発明の第2の実施例を説明する。Next, a second embodiment of the present invention will be described.
本実施例は、上述の第1実施例と同様に、2本の流速検
出管からなる複合流速検出管、負圧差検出手段および演
算手段から構成されている。しかし、第1の実施例と異
なり、第1の流速検出管2には、第11図の斜視図およ
び第12図の断面図に示すように互いに仰角の異なる開
口13.14が同じ側に複数個(本実施例では3個)穿
設されている。開口13の仰角θ3は最大負圧角度(お
よそ70°)よりも小さい65°に設定され、開口14
の仰角θ4は最大負圧角度よりも大きい756に設定さ
れている。This embodiment, like the first embodiment described above, is composed of a composite flow velocity detection tube consisting of two flow velocity detection tubes, negative pressure difference detection means, and calculation means. However, unlike the first embodiment, the first flow velocity detection tube 2 has a plurality of openings 13 and 14 on the same side with different elevation angles, as shown in the perspective view of FIG. 11 and the cross-sectional view of FIG. (three in this embodiment) are drilled. The elevation angle θ3 of the opening 13 is set to 65°, which is smaller than the maximum negative pressure angle (approximately 70°), and the opening 14
The elevation angle θ4 is set to 756, which is larger than the maximum negative pressure angle.
本実施例も、第1の実施例と同様の原理に基づいて、第
1の流速検出管2内部の負圧力と第2の流速検出管3内
部の負圧力との差を検出することにより、被測定流体の
流速を検出することができる。This embodiment is also based on the same principle as the first embodiment, by detecting the difference between the negative pressure inside the first flow velocity detection tube 2 and the negative pressure inside the second flow velocity detection tube 3. The flow velocity of the fluid to be measured can be detected.
また、被測定流体の流れの角度変位に対しても以下に示
すように安定した値を得ることができる。Furthermore, stable values can be obtained for angular displacement of the flow of the fluid to be measured as shown below.
たとえば、被測定流体の流れの方向が、上記実施例と同
様に、基本的な流れの方向1に対してα。For example, the flow direction of the fluid to be measured is α with respect to the basic flow direction 1, as in the above embodiment.
変位して方向2となったとする。この角度変位は、開口
13.14の双方の仰角を実質的にα°小さくする。こ
の影響は、第13図の特性図に示すように、開口13に
関しては負圧力の増大をもたらし、開口14に関しては
負圧力の減少をもたらす。Suppose that it is displaced and becomes direction 2. This angular displacement substantially reduces the elevation angle of both apertures 13.14 by α°. This effect results in an increase in the negative pressure with respect to the opening 13 and a decrease in the negative pressure with respect to the opening 14, as shown in the characteristic diagram of FIG.
この負圧力は互いに相殺し合い、結果として第1の流速
検出管2の内部の負圧力には変化が生じない。These negative pressures cancel each other out, and as a result, the negative pressure inside the first flow rate detection tube 2 does not change.
なお、本実施例では、θ3およびθ4はそれぞれ最大負
圧角度±5°の値であるが、これに限定されるものでは
なく、θ3は臨界負圧角度よりも大きく最大負圧角度よ
りも小さい任意の値をとることができ、また、θ4は最
大負圧角度よりも大きく安定最小角度よりも小さい任意
の値をとることができる。In this example, θ3 and θ4 are each a value of the maximum negative pressure angle ±5°, but the value is not limited to this, and θ3 is larger than the critical negative pressure angle and smaller than the maximum negative pressure angle. It can take any value, and θ4 can take any value that is larger than the maximum negative pressure angle and smaller than the minimum stable angle.
以上2つの実施例では、複合流速検出管4として、円筒
形の流速検出管2.3を単に並列配置したものを用いて
いるが、このような形状に限定されるものではなく、例
えば、第1の実施例に用いる複合流速検出管4を例にと
ると、第14図(a)〜(C)の断面図に示すような形
状のもの等が考えられる。また、開口5,6,7.13
.14の形状はいずれも円形であるが、第15図の斜視
図に示すような長円形状等も考えられる。さらに、第1
6図の断面図に示すように流速検出管の先端部に開口を
有するものであってもよい。In the above two embodiments, the cylindrical flow velocity detection tubes 2.3 are simply arranged in parallel as the composite flow velocity detection tube 4, but the shape is not limited to such a shape. Taking the composite flow velocity detection tube 4 used in the first embodiment as an example, it may have a shape as shown in the cross-sectional views of FIGS. 14(a) to 14(C). Also, openings 5, 6, 7.13
.. 14 are circular in shape, but an elliptical shape as shown in the perspective view of FIG. 15 is also conceivable. Furthermore, the first
As shown in the cross-sectional view of FIG. 6, the flow velocity detection tube may have an opening at its tip.
以上説明したように本発明の流速測定装置によれば、被
測定流体の流れによって第1の流速検出管の内部および
第2の流速検出管の内部にそれぞれ異なる値の負圧状態
が形成され、その負圧値の差から被測定流体の流速を求
めるものであり、被測定流体の流れる配管の口径がたと
え大きなものであっても、容易にその平均流速を求める
ことができる。As explained above, according to the flow rate measuring device of the present invention, negative pressure states of different values are formed inside the first flow rate detection tube and inside the second flow rate detection tube due to the flow of the fluid to be measured, and The flow velocity of the measured fluid is determined from the difference in the negative pressure values, and even if the diameter of the pipe through which the measured fluid flows is large, the average flow velocity can be easily determined.
また、負圧現象を利用しているので、被測定流体中に粉
塵が含まれていても、その粉塵が流速検出管内に流入し
難い。そのため、長期に渡ってメンテナンスフリーでの
測定が可能である。Furthermore, since a negative pressure phenomenon is utilized, even if dust is contained in the fluid to be measured, the dust is unlikely to flow into the flow velocity detection tube. Therefore, maintenance-free measurement is possible over a long period of time.
さらに、たとえ被測定流体の流れに揺れが生じていても
、その揺れに伴う第1の開口での負圧力の変化と第2の
開口での負圧力の変化は互いに相反するので、結果とし
て第1の流速検出管内の内部負圧力には変化が無く、一
方、第3の開口における負圧力は、被測定流体の流れの
揺れに対し、元来はとんど変化しないため、被測定流体
の流れの揺れによる測定誤差がない。したがって、非常
に高精度の流速測定が可能となる。Furthermore, even if fluctuations occur in the flow of the fluid to be measured, the changes in the negative pressure at the first opening and the changes in the negative pressure at the second opening due to the fluctuations contradict each other. There is no change in the internal negative pressure in the first flow velocity detection tube, and on the other hand, the negative pressure in the third opening does not change much in response to fluctuations in the flow of the fluid to be measured. There are no measurement errors due to flow fluctuations. Therefore, very highly accurate flow velocity measurement is possible.
第1図は本発明の一実施例を示す構成図、第2図は本実
施例における複合流速検出管4の斜視図、第3図はその
m−m ”断面図、第4図は本発明の動作原理を説明す
るのに用いた実験装置の外観図、第5図はこの実験に用
いた流速検出管の斜視図、第6図は実験結果を示すもの
で流速検出管の内部圧力と仰角θとの関係を示すグラフ
、第7図は第6図の部分拡大図、第8図は被測定流体の
流れの揺れに対する開口5,6における負圧力の変化を
説明するための特性図、第9図は負圧差検出手段8の他
の例を示す構成図、第10図は第9図における微小流量
検出手段19の説明図、第11図は本発明の第2の実施
例に用いる複合流速検出管の斜視図、第12図はそのx
u−xn’断面図、第13図は被測定流体の流れの揺れ
に対する開口13.14における負圧力の変化を説明す
るための特性図、第14図は複合流速検出管4の他の例
を示す断面図、第15図は複合流速検出管4の他の例を
示す斜視図、第16図は流速検出管2,3の他の例を示
す断面図である。
1・・・パイプ、2・・・第1の流速検出管、3・・・
第2の流速検出管、4・・・複合流速検出管、5,6.
7゜13.14・・・開口、8・・・負圧差検出手段、
9.10・・・圧力計、11.12・・・演算手段。Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a perspective view of a composite flow velocity detection tube 4 in this embodiment, Fig. 3 is a cross-sectional view along the mm-m'' line, and Fig. 4 is a diagram of the present invention. Fig. 5 is a perspective view of the flow velocity detection tube used in this experiment, and Fig. 6 shows the experimental results, showing the internal pressure and elevation angle of the flow velocity detection tube. Graph showing the relationship between θ and FIG. 9 is a configuration diagram showing another example of the negative pressure difference detection means 8, FIG. 10 is an explanatory diagram of the minute flow rate detection means 19 in FIG. 9, and FIG. 11 is a diagram showing the composite flow rate used in the second embodiment of the present invention. A perspective view of the detection tube, Fig. 12 shows its x
u-xn' sectional view, FIG. 13 is a characteristic diagram for explaining the change in negative pressure at the opening 13.14 with respect to fluctuations in the flow of the fluid to be measured, and FIG. 14 shows another example of the composite flow velocity detection tube 4. 15 is a perspective view showing another example of the composite flow rate detection tube 4, and FIG. 16 is a sectional view showing another example of the flow rate detection tubes 2 and 3. 1... Pipe, 2... First flow velocity detection tube, 3...
Second flow velocity detection tube, 4... Composite flow velocity detection tube, 5, 6.
7゜13.14...Opening, 8...Negative pressure difference detection means,
9.10...Pressure gauge, 11.12...Calculating means.
Claims (2)
度であって被測定流体から負圧力を受け得る最小角度)
よりも大きく、安定最小角度(被測定流体の上流を基準
とする角度であって被測定流体から受ける負圧力が角度
に係わらずほぼ一定となる最小角度)よりも小さい仰角
をもって被測定流体中に露出する第1の開口と、臨界負
圧角度より大きく、安定最小角度より小さい仰角をもち
、被測定流体の基本的な流れの方向を基準にして第1の
開口と反対側において被測定流体中に露出する第2の開
口とを有する第1の流速検出管と、安定最小角度よりも
大きい仰角もって被測定流体中に露出する第3の開口を
有する第2の流速検出管と、第1の流速検出管内に生じ
た負圧と第2の流速検出管内に生じた負圧の差から被測
定流体の流速を算出する演算手段とを備えた流速測定装
置。(1) Critical negative pressure angle (the minimum angle with respect to the upstream of the fluid to be measured that can receive negative pressure from the fluid to be measured)
, and smaller than the minimum stable angle (the minimum angle with respect to the upstream of the measured fluid at which the negative pressure received from the measured fluid is approximately constant regardless of the angle). a first aperture that is exposed and an elevation angle that is greater than the critical negative pressure angle and less than the minimum stable angle; a second flow velocity detection tube having a second opening exposed to the measured fluid; a second flow velocity detection tube having a third opening exposed into the fluid to be measured with an elevation angle greater than the minimum stable angle; A flow rate measuring device comprising a calculation means for calculating a flow rate of a fluid to be measured from a difference between a negative pressure generated in a flow rate detection tube and a negative pressure generated in a second flow rate detection tube.
定流体の上流を基準とする角度であって被測定流体から
受ける負圧力が最大となる角度)よりも小さい仰角をも
って被測定流体中に露出する第1の開口と、最大負圧角
度よりも大きく、安定最小角度よりも小さい仰角をもっ
て被測定流体中に露出する第2の開口とを有する第1の
流速検出管と、安定最小角度よりも大きい仰角もって被
測定流体中に露出する第3の開口を有する第2の流速検
出管と、第1の流速検出管内に生じた負圧と第2の流速
検出管内に生じた負圧の差から被測定流体の流速を算出
する演算手段とを備えた流速測定装置。(2) The fluid to be measured has an elevation angle that is larger than the critical negative pressure angle and smaller than the maximum negative pressure angle (an angle based on the upstream of the fluid to be measured, at which the negative pressure received from the fluid to be measured is maximum). a first flow velocity sensing tube having a first opening exposed into the fluid to be measured with an elevation angle greater than the maximum negative pressure angle and less than the stable minimum angle; a second flow velocity detection tube having a third opening exposed in the fluid to be measured with an elevation angle greater than the angle; a negative pressure generated within the first flow velocity detection tube; and a negative pressure generated within the second flow velocity detection tube. a calculation means for calculating the flow velocity of a fluid to be measured from the difference between the two.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP188987A JPS63171322A (en) | 1987-01-09 | 1987-01-09 | Flow velocity measuring instrument |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP188987A JPS63171322A (en) | 1987-01-09 | 1987-01-09 | Flow velocity measuring instrument |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS63171322A true JPS63171322A (en) | 1988-07-15 |
Family
ID=11514143
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP188987A Pending JPS63171322A (en) | 1987-01-09 | 1987-01-09 | Flow velocity measuring instrument |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS63171322A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06138134A (en) * | 1992-10-28 | 1994-05-20 | Hokuriku Nogyo Shikenjo | Flow-velocity measuring method of fluid |
WO2001075374A1 (en) * | 2000-04-04 | 2001-10-11 | Federspiel Clifford C | Pressure based flow rate measurement device integrated with blades of a damper |
-
1987
- 1987-01-09 JP JP188987A patent/JPS63171322A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06138134A (en) * | 1992-10-28 | 1994-05-20 | Hokuriku Nogyo Shikenjo | Flow-velocity measuring method of fluid |
JPH07117550B2 (en) * | 1992-10-28 | 1995-12-18 | 農林水産省北陸農業試験場長 | Non-rotating fluid velocity measuring method and device |
WO2001075374A1 (en) * | 2000-04-04 | 2001-10-11 | Federspiel Clifford C | Pressure based flow rate measurement device integrated with blades of a damper |
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