JP2962847B2 - Variable venturi type constant flow measurement control device - Google Patents

Variable venturi type constant flow measurement control device

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Publication number
JP2962847B2
JP2962847B2 JP3251491A JP3251491A JP2962847B2 JP 2962847 B2 JP2962847 B2 JP 2962847B2 JP 3251491 A JP3251491 A JP 3251491A JP 3251491 A JP3251491 A JP 3251491A JP 2962847 B2 JP2962847 B2 JP 2962847B2
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JP
Japan
Prior art keywords
flow rate
cross
sectional area
pressure
slot
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 - Fee Related
Application number
JP3251491A
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Japanese (ja)
Other versions
JPH04248414A (en
Inventor
茂 柳原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TSUKASA SOTSUKEN KK
Original Assignee
TSUKASA SOTSUKEN KK
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Application filed by TSUKASA SOTSUKEN KK filed Critical TSUKASA SOTSUKEN KK
Priority to JP3251491A priority Critical patent/JP2962847B2/en
Publication of JPH04248414A publication Critical patent/JPH04248414A/en
Application granted granted Critical
Publication of JP2962847B2 publication Critical patent/JP2962847B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は流体特に圧縮性流体の流
量を一定に制御する必要のあるプロセス工業、その他の
各種プラント、及び自動車排出ガスの計測などの公害防
止技術の分野に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of pollution control technology such as the process industry which requires constant control of the flow rate of a fluid, especially a compressible fluid, various other plants, and the measurement of automobile exhaust gas.

【0002】[0002]

【従来の技術】絞り流量計には各種あるが、流量を一定
に制御できる装置として臨界ノズル(クリティカルフロ
―ベンチュリ(図3及び渡辺紀之、小宮勤一、他;臨界
ノズルの特性、計測自動制御学会論文集、Vol.1
2, No.5,昭和51年10月,P64〜69参
照))が実用されている。この場合には、下流の圧力が
ある圧力以下に維持できれば、ノズル下流の圧力変化に
は影響を受けないで、ノズル上流の流体の温度圧力に応
じたその臨界流速(音速)と密度が、一定なスロ―ト部
断面積に対応して流量を決定する。従って、ノズル上流
の温度、圧力が一定ならば流量は一定に制御される。し
かし、この場合には上流の温度と圧力条件が変化すれ
ば、臨界流速や密度が変化するので、流量が一定とは必
ずしも言えない場合がある。更に、臨界流(クリティカ
ルフロ―)を発生させるに充分な圧力差は、臨界流に達
する点の圧力Pc =(2/K+1)K/(K-1) ・Po (こ
こに、K=流体の比熱比、Po はノズル入口のよどみ点
圧力)との比較において(Po −Pc )の約15%以上
の大きい値にする必要がある。加えてこの場合は流量が
可変できない制約がある。
2. Description of the Related Art There are various types of throttle flowmeters. As a device capable of controlling the flow rate constantly, a critical nozzle (critical flow venturi (see FIG. 3 and Noriyuki Watanabe, Koichi Komiya, et al .; characteristics of critical nozzle, automatic measurement control) Journal Proceedings, Vol.
2, No. 5, October 1979, see pages 64 to 69)). In this case, if the downstream pressure can be maintained at a certain pressure or less, the critical flow velocity (sonic velocity) and density according to the temperature and pressure of the fluid upstream of the nozzle are constant without being affected by the pressure change downstream of the nozzle. Determine the flow rate in accordance with the appropriate slot cross-sectional area. Therefore, if the temperature and pressure upstream of the nozzle are constant, the flow rate is controlled to be constant. However, in this case, if the upstream temperature and pressure conditions change, the critical flow rate and density change, so that the flow rate may not always be constant. Furthermore, the pressure difference sufficient to generate a critical flow (critical flow) is determined by the pressure P c = (2 / K + 1) K / (K−1) · P o (where K = specific heat ratio of the fluid, P o should be greater than about 15% (P o -P c) in comparison with the nozzle stagnation pressure at the inlet). In addition, in this case, there is a restriction that the flow rate cannot be changed.

【0003】スロ―ト部の流路断面積を可変にしたクリ
ティカルフロ―ベンチュリが発表されている。(U,
S.Patent 3,524,344, Aug.1
8,1970参照)
[0003] A critical flow venturi in which the cross-sectional area of the flow path in the slot portion is variable has been disclosed. (U,
S. Patent 3,524,344, August. 1
8, 1970)

【0004】この場合は流量はスロ―ト部の流速が音速
に達して一定であることを前提としているため、スロ―
ト部の圧力を測定しないが、下流側はスロ―トの面積が
変っても十分にクリティカルフロ―に達するために大き
な圧力降下を必要とし大容量の吸引ポンプが必要とな
る。更に、中心のニ―ドル状の流路断面積可変のための
コ―ン形状物体が片持ち支持であることから振動を生じ
易く、また下流側、すなわち流路断面積拡大側でコ―ン
形状物体の断面積が大きくなっていることから、圧力回
復に損失が大きく、形状的にも大流量の装置に適さな
い。特にクリティカルフロ―を前提にすることは吸引の
エネルギ―を大きくすることになり、測定・制御のため
のエネルギ―損失が過大となる。
In this case, the flow rate is based on the assumption that the flow velocity in the slot reaches the sonic speed and is constant.
Although the pressure at the port is not measured, the downstream side requires a large pressure drop to sufficiently reach the critical flow even if the area of the slot changes, requiring a large-capacity suction pump. Further, since the cone-shaped object for varying the cross-sectional area of the central needle shape is cantilevered, vibration is easily generated, and the cone is formed on the downstream side, that is, on the enlarged side of the cross-sectional area of the flow path. Since the cross-sectional area of the shaped object is large, loss in pressure recovery is large, and the shape is not suitable for a device having a large flow rate. In particular, assuming the critical flow, the energy of suction is increased, and the energy loss for measurement and control becomes excessive.

【0005】[0005]

【発明が解決しようとする課題】従来のクリティカルフ
ロ―ベンチュリ管では、比較的簡単な装置で流量を一定
にできる特徴があるが、例えば上流にフィルタ濾紙等を
配置して微粒子などをサンプリングする場合に、フィル
タの通過抵抗が次第に増加していくと、一定断面積のク
リティカルフロ―ベンチュリではフィルタ上流の質量流
量を一定にすることができない。更に吸引ポンプに要す
る圧力差(吸引負圧)が大きくなるなどの問題が生じ
る。またCFV−CVSとして知られるクリティカルフ
ロ―ベンチュリを用いた自動車排ガスの一定流量希釈サ
ンプリング装置においても、エンジンからの排気ガス流
量や温度が変化すると、クリティカルフロ―ベンチュリ
の温度条件が変化するなどの問題がある。
The conventional critical flow venturi tube has a feature that the flow rate can be kept constant by a relatively simple device. For example, when a filter paper or the like is arranged upstream to sample fine particles or the like. Furthermore, as the passage resistance of the filter gradually increases, the mass flow upstream of the filter cannot be made constant in a critical flow venturi having a constant cross-sectional area. Further, problems such as a large pressure difference (suction negative pressure) required for the suction pump occur. Also, in a constant flow dilution sampling apparatus for automobile exhaust gas using a critical flow venturi known as CFV-CVS, a problem such as a change in the temperature condition of the critical flow venturi when the exhaust gas flow rate or temperature from the engine changes. There is.

【0006】本発明は流体の圧力温度条件が変化して
も、質量流量を一定制御できることと、指定する流量が
任意に選択し設定できること、更に測定に必要なエネル
ギ―損失を抑制することを課題としている。
An object of the present invention is to enable constant control of the mass flow rate even when the pressure and temperature conditions of the fluid change, to be able to arbitrarily select and set a specified flow rate, and to suppress energy loss required for measurement. And

【0007】[0007]

【課題を解決するための手段】前記の3つの大きな課題
を解決するために、本発明は、絞りによる流量測定にお
いてエネルギ―損失の最も少ないベンチュリ管方式を採
用し、そのベンチュリ管のスロ―ト部の断面積を可変に
できるようにすると共に、このベンチュリ管によって流
量測定を実施しながら同時にこれによって流量制御を行
う手段を提供するものである。すなわち、ベンチュリ管
を環状流路断面をもつ形状として、中心部の円形断面を
管軸に沿って面積が滑かに変化するように構成し、かつ
ベンチュリ管のスロ―ト部が中心部の円形断面の物体の
管軸方向の移動によっても固定された外周部の一定な位
置であるような形状として、スロ―ト部の静圧力を常に
測定できるようにする。また中心部の円形断面の物体は
管軸に沿って移動できる構造とし、その位置は常に検出
または決定されて、スロ―ト部の断面積は物体の位置の
関数として既知とすることができるようにする。そし
て、この中心部の円形断面の物体の位置はベンチュリ管
内に配置されたサ―ボモ―タにより、自動的に制御でき
るようにする。一方、ベンチュリ管の流量は、上流部の
流体の温度、圧力及びスロ―ト部の圧力の連続的測定か
ら常に質量流量または体積流量として計算される回路を
設け、指定された流量との比較によって、ベンチュリ管
のスロ―ト部を構成する中心部の円形断面の物体の位置
を自動制御する。
SUMMARY OF THE INVENTION In order to solve the above three major problems, the present invention employs a Venturi tube system which has the least energy loss in flow measurement by a throttle, and the slot of the Venturi tube is used. The present invention provides a means for making the cross-sectional area of the section variable, and for controlling the flow rate while simultaneously performing the flow rate measurement by the Venturi tube. That is, the Venturi pipe is formed into a shape having an annular flow path cross section, and the circular cross section at the center is configured so that the area changes smoothly along the pipe axis, and the slot part of the Venturi pipe is circular at the center. The static pressure of the throat portion is always measured by making the shape such that it is a fixed position on the outer peripheral portion fixed also by the movement of the object of the cross section in the tube axis direction. In addition, the object with a circular cross section at the center is designed to be movable along the pipe axis, and its position is always detected or determined, so that the cross-sectional area of the slot can be known as a function of the position of the object. To The position of the object having a circular cross section at the center can be automatically controlled by a servomotor arranged in the Venturi tube. On the other hand, the flow rate of the venturi pipe is always calculated as a mass flow rate or a volume flow rate based on the continuous measurement of the temperature and pressure of the fluid in the upstream section and the pressure in the slot section. Automatically controls the position of an object having a circular cross section at the center which constitutes the slot of the Venturi tube.

【0008】[0008]

【作用】前述の手段によって、環状の流路断面を持つベ
ンチュリ管のスロ―ト部は、その流路断面積が可変にで
きると共に既知であり、必要に応じてその流量係数も既
知として、流体の温度、圧力、及びベンチュリ管入口と
スロ―ト部の差圧力から、質量流量または実体積流量は
計算により求めることができる。また、スロ―ト部の断
面積を変化させ制御することにより流量を変化させ制御
することができる。そして、指定された流量に合致する
ように、自動的にサ―ボ機構によって、その時の上流の
圧力、温度などの条件に応じた質量流量または実体積流
量を測定しながら制御作用する。
According to the above-mentioned means, the throat portion of the Venturi tube having an annular flow path cross section has a variable flow path cross-sectional area and a known flow rate coefficient if necessary. The mass flow rate or the actual volume flow rate can be obtained by calculation from the temperature, the pressure, and the differential pressure between the venturi inlet and the slot section. Also, the flow rate can be changed and controlled by changing and controlling the cross-sectional area of the slot. The servo mechanism automatically controls and measures the mass flow rate or the actual volume flow rate according to the conditions such as upstream pressure and temperature at that time so as to match the designated flow rate.

【0009】この測定制御作用は、下流側の圧力と流量
特性、例えば吸引ポンプの圧力と流量の関係にも関係し
て、自動的に指定された流量に制御することになる。こ
の場合、スロ―ト部においてクリティカルフロ―を生ず
る必要は必ずしもないので、ポンプの吸引能力は比較的
小さくて済む。普通には絞り流量測定方式におけるエネ
ルギ―損失を最小にすることが可能であり、特に大流量
において絞りによるエネルギ―損失を小さくできる作用
効果が期待できる。
In this measurement control operation, the flow rate is automatically controlled to a specified flow rate in relation to the pressure and flow rate characteristics on the downstream side, for example, the relationship between the pressure and the flow rate of the suction pump. In this case, it is not always necessary to generate a critical flow in the slot, so that the suction capacity of the pump can be relatively small. Normally, it is possible to minimize the energy loss in the throttle flow measurement method, and it can be expected to have the effect of reducing the energy loss due to the throttle particularly at a large flow rate.

【0010】[0010]

【実施例】以下、本発明の具体的実施例を、図1及び図
2を参照して説明する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to FIGS.

【0011】図2は本発明の一実施例を採用した燃焼排
ガスの微粒子試料採取装置における流量制御装置の説明
図である。図1は図2に示された本発明の一実施例の可
変ベンチュリ式定流量測定制御装置の可変ベンチュリ管
部の詳細を示す縦断面図である。図1においてベンチュ
リ管1の上流直管部11に流体の温度t1 を測定する温
度センサ12と静圧力P1 を取出す導管口13を設け
て、その下流側に外側断面積縮小部14を経て、スロ―
ト部15に静圧検出孔16を複数個備え、スロ―ト静圧
平均環17から静圧力Pt が取り出せるようにする。ス
ロ―ト部15の下流側には緩かに断面積が拡大する外側
断面積拡大部18が連がり、そのさらに下流に下流直管
部19が設けられている。ベンチュリ管の中心部の管軸
にはスロ―ト部近傍で円形の断面積が管軸方向に沿って
変化する面21を有する可動体2が配置され、その上流
側の直管部22はベンチュリ管内に同心に支柱36によ
り固定されたサ―ボナセルの直管部33に摺動可能に嵌
合して、回転を制約されて軸方向に移動可能に構成す
る。可動体2の下流側は細く長いガイド棒23を構成
し、ガイド支柱25に保持される直動軸受26によって
管軸中心において軸に沿って滑かに平行移動可能に支持
されると共に、その変位の指標xが電気信号として検出
される装置41を設ける。可動体2の内周側にはナット
27が配置され、ナセル内部に固定されたサ―ボモ―タ
31の回転軸32に設けられたねじ34と螺合される。
FIG. 2 is an explanatory view of a flow control device in a device for collecting particulates of flue gas employing one embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing details of a variable venturi tube section of the variable venturi-type constant flow rate measurement control device of one embodiment of the present invention shown in FIG. In FIG. 1, a temperature sensor 12 for measuring the temperature t 1 of the fluid and a conduit port 13 for taking out the static pressure P 1 are provided in an upstream straight pipe portion 11 of the venturi tube 1, and a downstream side through an outer cross-sectional area reducing portion 14. , Slow
Comprising a plurality of electrostatic pressure Deana 16 in isolation portion 15, Ro - From preparative static pressure average ring 17 can be taken out the static pressure P t. An outer cross-sectional area enlarging section 18 whose cross-sectional area gradually increases is connected to the downstream side of the slot section 15, and a downstream straight pipe section 19 is provided further downstream thereof. A movable body 2 having a surface 21 whose circular cross-sectional area changes along the tube axis direction near the slot portion is disposed on a tube axis in the center of the Venturi tube, and a straight tube portion 22 on the upstream side of the movable body 2 has a venturi. It is slidably fitted to the straight pipe part 33 of the servona cell fixed concentrically in the pipe by the support column 36, and is configured to be restricted in rotation and movable in the axial direction. The downstream side of the movable body 2 constitutes a thin and long guide rod 23, which is supported by a linear motion bearing 26 held by a guide support 25 so as to be able to move smoothly and parallel along the axis at the center of the tube axis. A device 41 is provided in which the index x is detected as an electric signal. A nut 27 is arranged on the inner peripheral side of the movable body 2 and is screwed with a screw 34 provided on a rotating shaft 32 of a servomotor 31 fixed inside the nacelle.

【0012】可動体2はサ―ボモ―タ31の回転によっ
て、ベンチュリ管軸に沿って平行移動し、その変位xに
よってスロ―ト部の環状流路断面積F(s)が変化す
る。この関係はスロ―ト部の外周径d0 と内周径dx に
より次のようになる。
The movable body 2 moves parallel to the axis of the Venturi tube by the rotation of the servomotor 31, and the displacement x changes the annular flow path cross-sectional area F (s) of the slot. This relationship is as follows according to the outer diameter d0 and the inner diameter dx of the slot.

【0013】f(s)=π/4(d0 2 −dx 2 ) ここで dx =a+bx で示されるとすれば、f
(s)=π/4(d0 2 −a2 −2abx−b22
としてxの関数となる。
[0013] if represented by f (s) = π / 4 (d0 2 -dx 2) where dx = a + bx, f
(S) = π / 4 ( d0 2 -a 2 -2abx-b 2 x 2)
Is a function of x.

【0014】ベンチュリ管入口径d1 とF(s)から絞
り比β2が次のように求められる。β2 =(d0 2 −a2
−2abx−b22 )/d1 2
The throttle ratio β 2 is obtained from the venturi pipe inlet diameter d 1 and F (s) as follows. β 2 = (d 0 2 −a 2
-2abx-b 2 x 2) / d1 2

【0015】ベンチュリ管による流量測定は、入口圧力
1 とスロ―ト部の圧力pt 及び流体の比重などと、ス
ロ―ト部の流路断面面積によって定まり、一般にはスロ
―ト部でクリティカルフロ―(音速)に達しない範囲で
は下記の数式1のように表わせる。Qを体積流量(m3
/s)とし、流量係数をαとし比重量をγとする。
The flow rate measurement by venturi inlet pressure P 1 and Ro - and such pressure p t and fluid specific gravity of isolation portion, Ro - determined by the flow cross-section area of the isolation portion, generally Ro - critical in isolation portions In the range not reaching the flow (sound speed), it can be expressed as the following equation 1. Q is the volumetric flow rate (m 3
/ S), the flow coefficient is α, and the specific weight is γ.

【0016】[0016]

【数1】 (Equation 1)

【0017】流体が圧縮性の場合には、膨脹補正係数ε
を用いて、下記の数式2で表わす。
If the fluid is compressible, the expansion correction coefficient ε
And is represented by the following equation (2).

【数2】 (Equation 2)

【0018】ここで、αはRe数とβの関数であるが、
Re数がある程度以上大きいときは下記の数式3のよう
にβの関数と見なすことができる。
Here, α is a function of the Re number and β,
When the Re number is larger than a certain value, it can be regarded as a function of β as in the following Expression 3.

【0019】[0019]

【数3】 (Equation 3)

【0020】またεはP1 とPt 及びβの関数として下
記の数式のように表わせる。 ε=(Pt /P11/K {K/(K−1)} ×[{1−(Pt /P1 2/K }/{1−(Pt /P1 )}] ×[(1−β4 )/{(1−β4 )(Pt /P12/K }]1/2
Ε can be expressed as the following equation as a function of P 1 , P t and β. ε = (P t / P 1 ) 1 / K {K / (K-1)} × [{1- (P t / P 1) 2 / K} / {1- (P t / P 1)}] × [(1-β 4 ) / {(1-β 4 ) (P t / P 1) 2 / K}] 1/2

【0021】ここにKは気体の比熱比で空気のように2
原子分子ではK=1.4としてよい。
Here, K is the specific heat ratio of gas, which is 2 like air.
In an atomic molecule, K may be set to 1.4.

【0022】更に重量流量W(Kgf/s)は次のよう
になる。 W=γQ
Further, the weight flow rate W (Kgf / s) is as follows. W = γQ

【0023】以上の関係からベンチュリ管における流量
は、入口の温度t1 と圧力P1 、スロ―ト部の圧力Pt
または差圧(P1 −Pt )を測定し、スロ―ト部の流路
断面積F(s)を知り、絞り比β2 をが判れば、計算に
より求めることができる。
From the above relationship, the flow rate in the Venturi tube depends on the inlet temperature t 1 and pressure P 1 , and the slot pressure P t.
Alternatively, if the differential pressure (P 1 -P t ) is measured, the flow path cross-sectional area F (s) of the slot portion is known, and the throttle ratio β 2 is known, it can be obtained by calculation.

【0024】計算回路45には、可動体の変位xからF
(s)を求め、β2 を計算する回路をもち、更に入口温
度t1 や圧力P1から流体のγを推定し、圧力Pt また
は差圧力P1 −Pt を測定して、流量QまたはWを求め
る計算機を内蔵して、その出力を比較回路46に入力す
る。比較回路46には指定流量が設定しており、測定・
計算流量との差に応じた制御信号がサ―ボ増幅器47に
伝達され、サ―ボ増幅器の出力によってサ―ボモ―タ3
1が駆動される。サ―ボモ―タ31は測定・計算流量が
指定流量より大きいとき、ベンチュリ管のスロ―ト部の
流路断面面積F(s)が小さくなるように、xを増加さ
せdx を大きくする方向に回転し、測定・計算流量が指
定流量に一致するように、自動制御する。
A calculation circuit 45 calculates F from the displacement x of the movable body.
(S) is obtained, and a circuit for calculating β 2 is provided. Further, γ of the fluid is estimated from the inlet temperature t 1 and the pressure P 1 , and the pressure P t or the differential pressure P 1 -P t is measured, and the flow rate Q Alternatively, a calculator for obtaining W is built in, and the output is input to the comparison circuit 46. The designated flow rate is set in the comparison circuit 46,
A control signal corresponding to the difference from the calculated flow rate is transmitted to the servo amplifier 47, and the servo motor 3 is controlled by the output of the servo amplifier.
1 is driven. When the measured / calculated flow rate is larger than the specified flow rate, the servo motor 31 increases x and increases dx so that the cross-sectional area F (s) of the venturi slot becomes smaller. It rotates and performs automatic control so that the measured / calculated flow rate matches the specified flow rate.

【0025】図2の実施例では、燃焼排ガスの流路51
内に吸引プロ―ブ52を挿入して試料ガスを分流採取
し、ハイボリュ―ムサンプラのフィルタ55を通過させ
て試料ガス中の微粒子をフィルタ上に堆積させて捕集す
る場合に、図1に例示する可変ベンチュリ式定流量測定
制御装置をフィルタ55の下流に配置して、ポンプ56
により試料ガスを吸引し吐出させ、その下流にガスメ―
タ57を配置して積算流量を測定しながら、排出できる
ように構成されている。この場合にはフィルタ55に微
粒子が堆積されると、試料ガスの通過抵抗が変化して通
過後の圧力すなわちP1 が次第に低下するが、質量流量
を一定に維持することが重要となる。すなわち、フィル
タに微粒子が堆積して、例えばP1 が400mmHg
(abs )まで低下するまでがこのフィルタの捕集限界
とすれば、その条件における流量をポンプ56の能力限
界内で可変ベンチュリ式定流量測定制御装置に設定して
おけば、P1 が初期に700mmHgあって徐々に低下
してきても流量測定と制御機構が作用して質量流量を一
定に保つことができる。
In the embodiment shown in FIG.
FIG. 1 shows an example in which a sample gas is divertedly collected by inserting a suction probe 52 into the inside thereof, and passing through a filter 55 of a high-volume sampler to deposit and collect fine particles in the sample gas on the filter. The variable venturi-type constant flow rate measurement control device is disposed downstream of the filter 55, and the pump 56
The sample gas is sucked and discharged by the
It is configured such that the discharge can be performed while the integrated flow rate is measured by arranging the heater 57. When particles are deposited on the filter 55 in this case, the pressure or P 1 after passing passage resistance of the sample gas is changed gradually decreases, it is important to keep the mass flow constant. That is, deposited particulate on the filter, for example, P 1 is 400mmHg
If until drops to (abs) is a collection limit of the filter, by setting the flow rate in the condition in the variable venturi type constant flow rate measurement control unit in the capacity limit of the pump 56, the P 1 initial Even if the flow rate gradually decreases at 700 mmHg, the flow rate measurement and control mechanism operates to keep the mass flow rate constant.

【0026】[0026]

【発明の効果】以上の説明から明らかなように、本発明
によれば次のような効果が得られる。
As apparent from the above description, the following effects can be obtained according to the present invention.

【0027】流量の測定と制御を行う場合に、ベンチュ
リ管として圧力損失が少ない条件で使用でき、大きい流
量に対してはスロ―ト部の断面積が大きく、すなわち絞
り比がβ2 が大きくなり、絞りによる圧力損失を小さく
できる。
When measuring and controlling the flow rate, it can be used as a Venturi tube under a condition with a small pressure loss. For a large flow rate, the cross-sectional area of the slot is large, that is, the throttle ratio β 2 becomes large. The pressure loss due to the restriction can be reduced.

【0028】入口の流体の温度や圧力が変化しても、質
量流量を測定することができるので、質量流量を一定に
制御することが可能である。
Even if the temperature or pressure of the fluid at the inlet changes, the mass flow rate can be measured, so that the mass flow rate can be controlled to be constant.

【0029】クリティカルフロ―ベンチュリのように、
スロ―ト部の流速を音速にまで大きくする必要がないの
で、吸引能力に制約がなく、吸引能力に応じた流量測定
と制御ができる。
Like a critical flow venturi,
Since it is not necessary to increase the flow velocity of the slot to the speed of sound, there is no restriction on the suction capacity, and flow measurement and control can be performed according to the suction capacity.

【図面の簡単な説明】[Brief description of the drawings]

【図1】この発明の可変ベンチュリ式定流量測定制御装
置の可変ベンチュリ管部を示す縦断面説明図である。
FIG. 1 is an explanatory longitudinal sectional view showing a variable venturi pipe section of a variable venturi-type constant flow rate measurement control device of the present invention.

【図2】燃焼排ガスの微粒子試料採取装置における流量
測定制御装置の縦断面説明図である。
FIG. 2 is a vertical cross-sectional explanatory view of a flow rate measurement control device in the device for collecting particulates of combustion exhaust gas.

【図3】従来の臨界ノズルを示す縦断面説明図である。FIG. 3 is an explanatory longitudinal sectional view showing a conventional critical nozzle.

【符号の説明】[Explanation of symbols]

1 ベンチュリ管 2 可動体 11 上流直管部 12 温度センサ 13 圧力導管 14 外側断面積縮小部 15 スロ―ト部 16 静圧検出孔 17 スロ―ト部静圧平均環 18 外側断面積拡大部 19 下流直管部 21 面 22 直管部 23 ガイド棒 25 ガイド支柱 26 直動軸受 27 ナット 31 サ―ボモ―タ 32 回転軸 33 直管部 34 ねじ 35 支柱 41 装置 45 計算回路 46 比較回路 47 サ―ボ増幅器 51 流路 52 吸引プロ―ブ 55 フィルタ 56 ポンプ 57 ガスメ―タ P1 ,P2 ,Pt 圧力 d0 外周径 dx 内周径 t1 温度DESCRIPTION OF SYMBOLS 1 Venturi pipe 2 Movable body 11 Upstream straight pipe part 12 Temperature sensor 13 Pressure conduit 14 Outer cross-sectional area reduction part 15 Slot part 16 Static pressure detection hole 17 Slot part static pressure average ring 18 Outer cross-sectional area expansion part 19 Downstream Straight pipe part 21 Surface 22 Straight pipe part 23 Guide rod 25 Guide support 26 Linear motion bearing 27 Nut 31 Servo motor 32 Rotating shaft 33 Straight pipe 34 Screw 35 Support 41 Device 45 Calculation circuit 46 Comparison circuit 47 Comparison circuit amplifier 51 the passage 52 suction pro - Bed 55 filter 56 pump 57 Gasume - data P 1, P 2, P t the pressure d0 peripheral diameter dx inner diameter t 1 temperature

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 流れ方向に沿って流路断面積が、滑かに
減少し、極小部を経由して、滑かにかつ十分に緩かに増
大するベンチュリ管において、管軸に沿って位置を変化
でき、その断面積が流れ方向に滑かに変化する部分を有
する物体を同軸に配置して、ベンチュリ管の極小部すな
わちスロ―ト部の断面積を可変とした可変ベンチュリ管
において、上流部の温度、圧力を入力すると共に、スロ
―ト部の静圧力と断面積を入力し、指定された質量流量
または指示された状態の体積流量に合致するような流量
計算機構をもち、更にその計算値に応じてベンチュリ管
のスロ―ト部断面積を自動的に制御するサ―ボモ―タを
備えた可変ベンチュリ式定流量測定制御装置。
Claims: 1. A venturi tube, in which the cross-sectional area of the flow path decreases smoothly along the flow direction and increases smoothly and sufficiently slowly via a local minimum, is located along the pipe axis. In a variable Venturi tube in which a cross-sectional area of a minimum portion of the Venturi tube, that is, a slot portion is variable, an object having a portion whose cross-sectional area changes smoothly in the flow direction is coaxially arranged. In addition to inputting the temperature and pressure of the section, the static pressure and cross-sectional area of the slot are input, and a flow rate calculation mechanism that matches the specified mass flow rate or the specified volume flow rate is provided. A variable venturi-type constant flow measurement control device equipped with a servomotor that automatically controls the cross-sectional area of the slot of the venturi tube according to the calculated value.
JP3251491A 1991-02-01 1991-02-01 Variable venturi type constant flow measurement control device Expired - Fee Related JP2962847B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3251491A JP2962847B2 (en) 1991-02-01 1991-02-01 Variable venturi type constant flow measurement control device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3251491A JP2962847B2 (en) 1991-02-01 1991-02-01 Variable venturi type constant flow measurement control device

Publications (2)

Publication Number Publication Date
JPH04248414A JPH04248414A (en) 1992-09-03
JP2962847B2 true JP2962847B2 (en) 1999-10-12

Family

ID=12361086

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3251491A Expired - Fee Related JP2962847B2 (en) 1991-02-01 1991-02-01 Variable venturi type constant flow measurement control device

Country Status (1)

Country Link
JP (1) JP2962847B2 (en)

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US6623160B2 (en) 2000-12-21 2003-09-23 Mccarthy, Jr. Joseph H. Method and system for cooling heat-generating component in a closed-loop system
US6698924B2 (en) 2000-12-21 2004-03-02 Tank, Inc. Cooling system comprising a circular venturi
US7461975B2 (en) 2000-12-21 2008-12-09 Tark, Inc. Method and system for cooling heat-generating component in a closed-loop system
US7093977B2 (en) 2000-12-21 2006-08-22 Tark, Inc. Method and system for cooling heat-generating component in a closed-loop system
US7484888B2 (en) 2000-12-21 2009-02-03 Tark, Inc. Method and system for cooling heat-generating component in a closed-loop system
US7255012B2 (en) * 2004-12-01 2007-08-14 Rosemount Inc. Process fluid flow device with variable orifice
JP5438884B2 (en) * 2006-12-14 2014-03-12 株式会社日立製作所 City gas production equipment
JP5089340B2 (en) * 2007-11-02 2012-12-05 株式会社司測研 Structure of variable cross-section venturi type exhaust gas flowmeter
JP5071392B2 (en) * 2009-01-08 2012-11-14 Jfeエンジニアリング株式会社 Fluid mixing method using Venturi tube
CN109459277B (en) * 2018-11-22 2024-04-05 国网浙江省电力有限公司电力科学研究院 Constant-speed control box applied to portable coal dust sampling device and application method of constant-speed control box

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Also Published As

Publication number Publication date
JPH04248414A (en) 1992-09-03

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