JP2575685Y2 - Control valve structure of mass flow controller - Google Patents
Control valve structure of mass flow controllerInfo
- Publication number
- JP2575685Y2 JP2575685Y2 JP1992019018U JP1901892U JP2575685Y2 JP 2575685 Y2 JP2575685 Y2 JP 2575685Y2 JP 1992019018 U JP1992019018 U JP 1992019018U JP 1901892 U JP1901892 U JP 1901892U JP 2575685 Y2 JP2575685 Y2 JP 2575685Y2
- Authority
- JP
- Japan
- Prior art keywords
- valve
- mass flow
- flow rate
- control valve
- flow controller
- 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 - Lifetime
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- Details Of Valves (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本考案は、大気中の微小粒子成分
を分析するための計測機器の部品に使用される質量流量
制御器の制御弁構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve structure of a mass flow controller used as a component of a measuring instrument for analyzing a fine particle component in the atmosphere.
【０００２】[0002]
【従来の技術】大気中の微小粒子成分(例えば、放射性
塵埃)に関する測定を行うには、一般的に塵埃をフィル
タで捕促し、前記塵埃(例えば、前記塵埃からの放射能)
を測定するという方法が取られる。精度の高い測定を行
うには、微小粒子を含む大気を一定流量で吸引する必要
がある。処が、フィルタに微小粒子が付着して行くと目
詰まりを発生し流速が低下して行き、一定流量で吸引し
続ける事が出来なくなる。そこで、フィルタの目詰まり
が発生しても一定流量で大気を吸引し続けるようにする
ために質量流量制御器が使用されるようになってきた。2. Description of the Related Art In order to measure a fine particle component (for example, radioactive dust) in the atmosphere, dust is generally captured by a filter, and the dust (for example, radioactivity from the dust) is collected.
Is measured. In order to perform highly accurate measurement, it is necessary to suck the atmosphere containing fine particles at a constant flow rate. However, when the fine particles adhere to the filter, clogging occurs, the flow velocity decreases, and it becomes impossible to continue suction at a constant flow rate. Therefore, mass flow controllers have come to be used in order to keep sucking the air at a constant flow rate even if filter clogging occurs.
【０００３】図２は、一般に使用されている質量流量制
御器(A)で、流体の流量測定を行うセンサ部(C)と、セン
サ部(C)に流れる流体の流量に比例して流量が流れるバ
イパス部(D)並びにバイパス部(D)とセンサ部(C)から流
出した流体が合流して外部装置に接続される出口継ぎ手
(25)に連通せる流路(12)(13)に設けられた制御弁(16)と
で構成されている。FIG. 2 shows a mass flow controller (A) generally used, in which a sensor section (C) for measuring the flow rate of a fluid and a flow rate in proportion to the flow rate of the fluid flowing through the sensor section (C) are shown. An outlet joint where the flowing bypass part (D) and the fluid flowing out of the bypass part (D) and the sensor part (C) are merged and connected to an external device
And a control valve (16) provided in flow paths (12) and (13) communicating with (25).
【０００４】図７は前記質量流量制御器(A)の制御弁構
造の断面図で、弁室(11)内には弁体(16)が昇降自在に収
納されており、バルブハウジング(14)の上面に配設され
た駆動部(15)に、ダイアフラム(19)を介してスプリング
(17)にて押圧付勢されている。弁体(16)の下面は弁座(1
8)に穿設された１次側バルブ流路(12)の出口に対向して
おり、弁体(16)の平坦下面全面が平坦な弁座(18)の上面
に当接・離間してその弁開度を調整し、１次側バルブ流
路(12)の出口から弁室(11)に流入する流体の質量流量を
制御するようになっている。図８が従来の制御弁構造に
よって質量流量制御を行った場合の(流量)対(流量設定
電圧)との関係図で、完全に弁体(16)を閉じた場合には
表示電圧は０Ｖを示し、設定電圧の増加と共に比例的に
質量流量が増加する。FIG. 7 is a sectional view of a control valve structure of the mass flow controller (A). A valve body (16) is housed in a valve chamber (11) so as to be able to move up and down, and a valve housing (14) is provided. The spring (15) is mounted on the drive unit (15)
It is urged by (17). The lower surface of the valve body (16) is
8) is opposed to the outlet of the primary valve flow path (12) drilled in the valve body (16), and the entire flat lower surface of the valve body (16) comes into contact with or separates from the upper surface of the flat valve seat (18). The valve opening is adjusted to control the mass flow rate of the fluid flowing into the valve chamber (11) from the outlet of the primary valve flow path (12). FIG. 8 is a diagram showing the relationship between (flow rate) and (flow rate setting voltage) when mass flow rate control is performed by the conventional control valve structure. When the valve body (16) is completely closed, the display voltage is 0 V. As shown, the mass flow rate increases proportionally with an increase in the set voltage.
【０００５】このような互いに平坦面で構成された弁体
(16)と弁座(18)とを有する質量流量制御器(A)を、大気
中の微小粒子分析用の計測機器の部品として使用した場
合、以下のような問題点がある。即ち、図７に示すよう
に大気中に微小粒子(22)が含まれていると次第に弁開度
の制御中に弁体(16)と弁座(18)との間を始め弁室(11)内
に微小粒子(22)が蓄積して目詰まりを発生させる。これ
により流量制御が困難になり、計測結果が次第に不正確
になるという欠点があった。[0005] Such a valve body composed of mutually flat surfaces.
When the mass flow controller (A) having the valve seat (18) and the mass flow controller (A) is used as a component of a measuring device for analyzing fine particles in the atmosphere, there are the following problems. That is, as shown in FIG. 7, when the fine particles (22) are contained in the atmosphere, the valve chamber (11) starts to move between the valve body (16) and the valve seat (18) gradually during the control of the valve opening. The fine particles (22) accumulate in the parentheses) to cause clogging. This has the disadvantage that flow control becomes difficult and the measurement results become increasingly inaccurate.
【０００６】[0006]
【考案が解決しようとする課題】本考案の解決課題は、
弁体と弁座との間は勿論、弁室内での微小粒子の蓄積を
出来るだけ少なくして目詰まりの発生を防止し、これに
よって長期間にわたって高い精度の計測結果を維持出来
るようにする事である。[Problems to be solved by the present invention]
Accumulation of fine particles in the valve chamber as well as between the valve body and the valve seat is minimized to prevent clogging, thereby maintaining high-accuracy measurement results over a long period of time. It is.
【０００７】[0007]
【課題を解決するための手段】本考案は、前記課題を解
決するために、 流体の流量測定を行うセンサ部(C)と、センサ部(C)
に流れる流体の流量に比例して流量が流れるバイパス部
(D)とを有し、バイパス部(D)とセンサ部(C)から流出し
た流体が合流して外部装置に接続される出口継ぎ手(3)
に連通せる流路(12)及び(13)間に制御弁(CV)を設けた質
量流量制御器(A)において、 制御弁(CV)の互いに当接・離間する弁体(16)と弁座
(18)の少なくともいずれか一方の当接面に弁体(16)と弁
座(18)との間に間隙(K)を形成するための突起(T)が突設
されている事を特徴とする。According to the present invention, there is provided a sensor unit (C) for measuring a flow rate of a fluid, and a sensor unit (C).
Section where the flow rate is proportional to the flow rate of the fluid flowing through
(D), an outlet joint (3) in which fluids flowing out of the bypass part (D) and the sensor part (C) are merged and connected to an external device.
In the mass flow controller (A) provided with a control valve (CV) between the flow paths (12) and (13) communicating with the valve, the valve body (16) and the valve that contact and separate from each other of the control valve (CV) seat
A projection (T) for forming a gap (K) between the valve body (16) and the valve seat (18) is provided on at least one of the contact surfaces of the (18). And
【０００８】これにより、制御弁(CV)を閉じた状態は勿
論、弁開度の制御中でも前記間隙(K)を通って微小粒子
(22)は大気と共に流出してしまい、間隙(K)には勿論、
弁室(11)内にも微小粒子(22)の蓄積が発生せず、微小粒
子(22)を含む大気を流通させても長期間にわたって目詰
まりを発生させるというような事がなく、高い計測精度
を維持する事ができる。Accordingly, the fine particles pass through the gap (K) while the control valve (CV) is closed and the valve opening is controlled.
(22) flows out with the atmosphere, and of course, in the gap (K),
Accumulation of fine particles (22) does not occur in the valve chamber (11), and clogging does not occur for a long time even if air containing fine particles (22) is circulated, high measurement Accuracy can be maintained.
【０００９】[0009]
【実施例】以下、本考案を図示実施例に従って詳述す
る。図１は本考案にかかる質量流量制御器(A)を部品と
した計測機器のフロー図で、(F1)は第１段フィルタで、
所定直径以上の微小粒子(22)を捕集し、それ以下の微小
粒子(22)だけが質量流量制御器(A)に大気とともに流れ
込むようにしている。(A)は質量流量制御器でその構造
については後述する。(F2)は第２段フィルタで、質量流
量制御器(A)を通過した微小粒子(22)のほとんどを捕促
できるようになっている。(S)は測定センサで、本実施
例では放射線計測センサが使用されている。(23)は吸引
ポンプで、計測機器(M)全体の吸引に供されるものであ
る。BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a flow chart of a measuring instrument having the mass flow controller (A) according to the present invention as a part, and (F1) is a first-stage filter.
The fine particles (22) having a diameter equal to or larger than a predetermined diameter are collected, and only the fine particles (22) having a diameter smaller than the predetermined diameter flow into the mass flow controller (A) together with the atmosphere. (A) is a mass flow controller, the structure of which will be described later. (F2) is a second-stage filter capable of capturing most of the fine particles (22) that have passed through the mass flow controller (A). (S) is a measurement sensor, and in this embodiment, a radiation measurement sensor is used. (23) is a suction pump used for suctioning the entire measuring device (M).
【００１０】図２は本実施例でも従来例でも使用される
質量流量制御器(A)の一実施例の縦断面図であり、両者
の相違は制御弁(CV)にあり、図３が本考案にかかる制御
弁(CV)の拡大断面図である。FIG. 2 is a longitudinal sectional view of one embodiment of a mass flow controller (A) used in both the present embodiment and the conventional example. The difference between the two is in the control valve (CV). It is an enlarged sectional view of the control valve (CV) concerning the invention.
【００１１】ボディ本体(9)には、その両端に入り口継
ぎ手(24)と出口継ぎ手(25)とがそれぞれ固着されてお
り、入り口継ぎ手(24)にガス流入用の入り口(2)が設け
られており、出口継ぎ手(25)にガス流出用の出口(3)が
設けられている。ボディ本体(9)には一端に開口する円
筒穴(10)が穿設されており、円筒穴(10)の穴底中央には
コントロールバルブ部(B)の弁室(11)に連通する１次側
バルブ流路(12)と、弁室(11)から他端に連通する２次側
バルブ流路(13)とが穿設されている。An inlet joint (24) and an outlet joint (25) are fixed to both ends of the body body (9), respectively. The inlet joint (24) is provided with an inlet (2) for gas inflow. The outlet joint (25) is provided with an outlet (3) for gas outflow. The body body (9) has a cylindrical hole (10) opened at one end, and the center of the bottom of the cylindrical hole (10) communicates with the valve chamber (11) of the control valve part (B). A secondary valve flow path (12) and a secondary valve flow path (13) communicating from the valve chamber (11) to the other end are provided.
【００１２】センサ部(C)は、センサ管(5)とスペーサ
(8)とで構成されており、ボディ本体(9)の上面に前記ス
ペーサ(8)が載設固定されており、このスペーサ(8)に２
つの管路(7a)(7b)が穿設されており、後述するバイパス
素子(6)を跨ぐように設けられている。センサ管(6)の周
囲には２本のヒータ(Hu)(Hd)が巻設されており、センサ
管(5)中を流れる流体の質量流量を測定するようになっ
ている。The sensor section (C) comprises a sensor tube (5) and a spacer.
The spacer (8) is mounted and fixed on the upper surface of the body (9).
Two pipes (7a) and (7b) are formed, and are provided so as to straddle a bypass element (6) described later. Two heaters (Hu) and (Hd) are wound around the sensor tube (6) so as to measure the mass flow rate of the fluid flowing through the sensor tube (5).
【００１３】バイパス素子(6)は、例えば帯状体の表面
に幅方向に凹溝をエッチングにて多数本凹設し、この帯
状体を芯棒の回りに巻設して軸方向にバイパス孔を構成
したようなものやセンサ管(5)のような毛細管を多数束
ねたものである。このように形成されたバイパス素子
(6)は図２に示すように円筒穴(10)内に嵌め込まれて使
用される。バイパス孔の数は、流量に合わせて適宜選択
される。In the bypass element (6), for example, a large number of concave grooves are formed in the surface of the band by etching in the width direction, and the band is wound around a core rod to form a bypass hole in the axial direction. This is a bundle of a large number of capillary tubes, such as those configured and a sensor tube (5). Bypass element thus formed
(6) is used by being fitted into a cylindrical hole (10) as shown in FIG. The number of bypass holes is appropriately selected according to the flow rate.
【００１４】コントロールバルブ部(B)は、図７に示す
ようにバルブハウジング(14)と駆動部(15)とで構成され
ており、バルブハウジング(14)に穿設された下面開口の
弁室(11)に前記１次側バルブ流路(12)の出口と２次側バ
ルブ流路(13)の入り口が開口している。図３の実施例で
は、弁室(11)内に制御弁(16)が昇降自在に収納されてお
り、バルブハウジング(14)の上面に配設された駆動部(1
5)に、ダイアフラム(19)を介してスプリング(17)にて押
圧付勢されている。制御弁(16)の下面は１次側バルブ流
路(12)の出口に一致しており、制御弁(16)の下面外周に
環状の突起(T)が突設されている。突起(T)の間は大気流
通路(21)となっており、制御弁(16)の閉塞状態でも微小
粒子(22)と共に大気が２次側バルブ流路(13)に流れるよ
うになっている。The control valve section (B) comprises a valve housing (14) and a drive section (15) as shown in FIG. 7, and a valve chamber having a lower surface opening formed in the valve housing (14). The outlet of the primary valve flow path (12) and the entrance of the secondary valve flow path (13) are open at (11). In the embodiment of FIG. 3, a control valve (16) is housed in a valve chamber (11) so as to be able to move up and down, and a drive unit (1) arranged on the upper surface of a valve housing (14).
5), a pressure is applied by a spring (17) via a diaphragm (19). The lower surface of the control valve (16) coincides with the outlet of the primary valve flow path (12), and an annular projection (T) is provided on the outer periphery of the lower surface of the control valve (16). An air flow passage (21) is formed between the projections (T), and the air flows into the secondary valve flow path (13) together with the fine particles (22) even when the control valve (16) is closed. I have.
【００１５】突起(T)によって形成される間隙(K)の寸法
並びに大気流通路(21)の幅は、第１フィルタ(F1)を通っ
て質量流量制御器(A)に流れ込む微小粒子(22)の直径よ
りやや大きく形成してあり、弁室(11)内に微小粒子(22)
が堆積する事なく２次側バルブ流路(13)に流れ込むよう
になっている。The size of the gap (K) formed by the projection (T) and the width of the air flow passage (21) are determined by the fine particles (22) flowing into the mass flow controller (A) through the first filter (F1). ) Is formed slightly larger than the diameter of the small particles (22) in the valve chamber (11).
Flows into the secondary valve flow path (13) without being deposited.
【００１６】本実施例における計測対象の微小粒子(22)
は、例えば大気中に含まれる放射性塵埃(22)である。第
１フィルタ(F1)は、例えばこのうち0.2mm以上の微小粒
子(22)を捕集し、0.2mm以下の微小粒子(22)を含む大気
を質量流量制御器(A)に送り込む。従って前述の間隙(K)
の幅並びに大気流通路(21)の幅は、この場合0.2mmより
やや大きく形成される事になる。Microparticles to be measured in this embodiment (22)
Is, for example, radioactive dust (22) contained in the atmosphere. The first filter (F1) captures, for example, fine particles (22) of 0.2 mm or more among them, and sends the atmosphere containing the fine particles (22) of 0.2 mm or less to the mass flow controller (A). Therefore, the aforementioned gap (K)
In this case, the width of the air flow passage 21 is slightly larger than 0.2 mm.
【００１７】次に、本実施例にかかる質量流量制御器
(A)を大気中の放射性粉塵(22)の測定に使用する場合を
例にとって説明する。この測定は単位時間当たりに一定
の質量流量で通過した大気中に含まれる放射性塵埃(22)
の量を検出する事を目的とするものである。まず、吸引
ファン(23)を作動させて放射性塵埃(22)を含む大気を、
第１フィルタ(F1)、質量流量制御器(A)、第２フィルタ
(F2)と言うように通過させ、大気の質量流量の測定を開
始する。前述のように0.2mm以上の微小粒子(22)は第１
フィルタ(F1)にて捕集され、これ以下の粒径の微小粒子
(22)が大気と共に質量流量制御器(A)に流入する。流入
大気の大部分はバイパス素子(6)を通過し、ごく少量の
大気がセンサ管(5)を通過する。Next, the mass flow controller according to the present embodiment
The case where (A) is used for measurement of radioactive dust (22) in the atmosphere will be described as an example. This measurement is based on radioactive dust (22) contained in the atmosphere that has passed at a constant mass flow rate per unit time.
The purpose is to detect the amount of First, the air containing the radioactive dust (22) is operated by operating the suction fan (23).
First filter (F1), mass flow controller (A), second filter
(F2) and start measuring the mass flow rate of the atmosphere. As described above, the fine particles (22) of 0.2 mm or more
Fine particles collected by the filter (F1) and having a particle size smaller than this
(22) flows into the mass flow controller (A) together with the atmosphere. Most of the incoming air passes through the bypass element (6), and only a small amount of air passes through the sensor tube (5).
【００１８】センサ管(5)を流れる流体は上流側ヒータ
(Hu)の熱を奪って下流側に流れ、下流側ヒータ(Hd)の加
熱量を抑制する。上流側ヒータ(Hu)では奪われた熱量を
補給して平衡温度に達するよう制御回路が上流側ヒータ
(Hu)を制御する。これにより両ヒータ(Hu)(Hd)への供給
電力のバランスが崩れ、この差を検出演算する事により
センサ管(5)に流れる大気の質量流量が検出される。こ
のような質量流量検出は一般的な方法である。The fluid flowing through the sensor tube (5) is an upstream heater
The heat of (Hu) is taken away and flows downstream, and the amount of heating of the downstream heater (Hd) is suppressed. In the upstream heater (Hu), the control circuit replenishes the removed heat and reaches the equilibrium temperature.
(Hu). As a result, the balance between the power supplied to the heaters (Hu) and (Hd) is lost, and the mass flow of the atmosphere flowing through the sensor tube (5) is detected by detecting and calculating the difference. Such mass flow detection is a common method.
【００１９】一方、バイパス素子(6)を流れる大気の流
量はセンサ管(5)の流量に比例しているから、全体のガ
ス流量はセンサ管(5)の流量に所定の係数を乗ずる事に
より簡単に知る事が出来る。そして、この出力はコント
ロールバルブ部(B)へフィードバックされ、制御部(15)
によって制御弁(16)が駆動されて弁室(11)を流れる大気
の質量流量が正確に制御される。On the other hand, since the flow rate of the atmosphere flowing through the bypass element (6) is proportional to the flow rate of the sensor pipe (5), the total gas flow rate is obtained by multiplying the flow rate of the sensor pipe (5) by a predetermined coefficient. You can easily find out. Then, this output is fed back to the control valve section (B), and the control section (15)
Accordingly, the control valve (16) is driven, and the mass flow rate of the atmosphere flowing through the valve chamber (11) is accurately controlled.
【００２０】バイパス素子(6)を出た流体はセンサ管(5)
を通った流体と合流して１次側バルブ流路(12)に入る。
この時、センサ管(5)からの信号電圧に比例して制御部
(15)が作動し、スプリング(17)の弾発力と協働して制御
弁(16)と弁座(18)との間隙を厳密に調整して１次側バル
ブ流路(12)から２次側バルブ流路(13)に流れる流体の質
量流量を厳しく制御する。本実施例では単位時間当たり
の大気の質量流量中に含まれる放射性塵埃(22)の量を正
確に測定するためのものであるから、質量流量制御器
(A)内を通過する大気の質量流量は一定に保たれる。本
実施例では例えば測定流量が６０リットル/minに設定さ
れている。このように１次側バルブ流路(12)から弁室(1
1)内に出る大気の質量流量が正確に規制され、然る後、
２次側バルブ流路(13)を通ってボディ(1)の外に出、第
２フィルタ(F2)に供給される。The fluid leaving the bypass element (6) is supplied to the sensor tube (5).
Merges with the fluid that has passed through and enters the primary valve flow path (12).
At this time, the control unit is in proportion to the signal voltage from the sensor tube (5).
(15) is actuated, and the gap between the control valve (16) and the valve seat (18) is strictly adjusted in cooperation with the resilience of the spring (17) to allow the primary valve flow path (12) to The mass flow rate of the fluid flowing in the secondary valve flow path (13) is strictly controlled. In this embodiment, since it is for accurately measuring the amount of radioactive dust (22) contained in the mass flow rate of the atmosphere per unit time, the mass flow controller
The mass flow rate of the atmosphere passing through (A) is kept constant. In this embodiment, for example, the measurement flow rate is set to 60 liter / min. In this way, the valve chamber (1
1) The mass flow rate of the atmosphere coming out is precisely regulated and then
The air exits the body (1) through the secondary valve flow path (13) and is supplied to the second filter (F2).
【００２１】第２フィルタ(F2)において、大気中に含ま
れた微小粒子(22)のほとんどが捕集され、微小粒子(22)
をほとんど含まない清浄空気が吸引ポンプを通って大気
放出される。吸引時間並びに単位時間当たりの吸引風量
は実験によって最適の値が選択される。このように選択
捕集された微小粒子(22)の帯びている放射能を測定し、
大気中の放射能量を決定する。In the second filter (F2), most of the fine particles (22) contained in the atmosphere are collected, and the fine particles (22) are collected.
The clean air containing almost no air is vented to the atmosphere through the suction pump. Optimum values of the suction time and the amount of suction air per unit time are selected by experiments. The radioactivity of the fine particles (22) selectively collected in this way is measured,
Determine the amount of radioactivity in the atmosphere.
【００２２】前記測定において、計測時間の経過と共に
第１フィルタ(F1)並びに第２フィルタ(F2)に微小粒子(2
2)が次第に蓄積し、大気の流通が次第に阻害されて圧損
が増大していく。圧損が増大し、第１フィルタ(F1)から
質量流量制御器(A)へ流入する空気量が減少するとセン
サ管(5)に流れる空気量も減少量に比例して減少する。
これをセンシングする事によって駆動部(15)を作動させ
て制御弁(16)の弁開度を減少量に比例させて開き、前記
減少量を補償する。これにより圧損の増大にも拘わら
ず、第２段フィルタ(F2)に流れ込む空気量は一定に保た
れる事になる。In the measurement, the fine particles (2) are applied to the first filter (F1) and the second filter (F2) as the measurement time elapses.
2) gradually accumulates, and the circulation of the atmosphere is gradually obstructed and the pressure loss increases. When the pressure loss increases and the amount of air flowing from the first filter (F1) to the mass flow controller (A) decreases, the amount of air flowing to the sensor tube (5) also decreases in proportion to the amount of decrease.
By sensing this, the drive unit (15) is operated to open the valve opening of the control valve (16) in proportion to the decrease amount, thereby compensating for the decrease amount. As a result, the amount of air flowing into the second-stage filter (F2) is kept constant despite the increase in pressure loss.
【００２３】図６は、本考案にかかる質量流量制御器
(A)の(流量)対(差圧)の関係を示すグラフである。制御
弁(16)を閉塞状態にしてセンサ管(5)の１次側と２次側
の差圧を次第に高めると、弁座(18)と弁体(16)との間隙
(K)を通って微小粒子(22)と共に大気が弁室(11)に流れ
込み、更に２次側バルブ流路(13)を通って第２段フィル
タ(F2)へ流れ込むのであるが、差圧の増大と共に比例的
に流量が増える。これが直線ＯＡで示される。この時、
前記間隙(K)は微小粒子(22)より大きいので微小粒子(2
2)は弁室(18)に溜る事なくを通過してしまう。FIG. 6 shows a mass flow controller according to the present invention.
3 is a graph showing the relationship between (flow rate) and (differential pressure) in (A). When the differential pressure between the primary side and the secondary side of the sensor pipe (5) is gradually increased by closing the control valve (16), the clearance between the valve seat (18) and the valve body (16) is increased.
(K) flows into the valve chamber (11) together with the fine particles (22), and further flows into the second stage filter (F2) through the secondary valve flow path (13). The flow rate increases proportionally with the increase of. This is indicated by the straight line OA. At this time,
Since the gap (K) is larger than the fine particles (22), the fine particles (2
2) passes without accumulating in the valve chamber (18).
【００２４】Ａ点に達したところで、駆動部(15)を作動
させて弁開度を制御し、質量流量制御行う。これによっ
て差圧の変動があっても質量流量制御器(A)を通過する
空気の質量流量は一定に保たれる。即ち、第１段、第２
段フィルタ(F1)(F2)の目詰まりによって圧損が増大し、
センサ管(5)の１次側と２次側の差圧が変動しても質量
流量制御器(A)を通過する空気の質量流量は一定に保た
れる事を意味している。図６では差圧が0.25〜0.5kg/cm
2の範囲(Ａ点からＢ点の範囲)で質量流量が一定に保た
れる事を示している。従って、本実施例における測定は
Ａ−Ｂ間で行なわれる事になる。When the point A is reached, the drive unit (15) is operated to control the valve opening and control the mass flow rate. As a result, the mass flow rate of the air passing through the mass flow controller (A) is kept constant even if the differential pressure fluctuates. That is, the first stage, the second stage
Pressure drop increases due to clogging of the stage filter (F1) (F2),
This means that the mass flow rate of the air passing through the mass flow controller (A) is kept constant even if the pressure difference between the primary side and the secondary side of the sensor tube (5) fluctuates. In Fig. 6, the differential pressure is 0.25-0.5kg / cm
It shows that the mass flow rate is kept constant in the range of 2 (range from point A to point B). Therefore, the measurement in this embodiment is performed between AB.
【００２５】Ｂ−Ｃ間はバルブ全開時の制御範囲を越え
た場合で、差圧の増大に比例して質量流量は再度増加し
ていく。尚、本実施例では弁体(16)の下面に突起(T)を
突設した場合を示したが、勿論これに限られず、弁座(1
8)の方に突起を設けても良い。Between B and C, the control range when the valve is fully opened is exceeded, and the mass flow rate increases again in proportion to the increase in the differential pressure. In this embodiment, the case in which the projection (T) is provided on the lower surface of the valve element (16) is shown. However, the present invention is not limited to this.
A projection may be provided on 8).
【００２６】[0026]
【効果】本考案は、互いに当接・離間する弁体と弁座の
少なくともいずれか一方の当接面に弁体と弁座との間に
常に間隙を形成するための突起が形成されているので、
制御弁の閉塞時は勿論、弁開度の制御によって質量流量
制御を行っている場合でも弁座と制御弁との間隙を通っ
て微小粒子が大気と共に弁室に流れ込み、更に２次側流
路を通って次工程へと流出してしまうので、弁室に微小
粒子が溜る事がない。その結果、目詰まりを発生する事
がなく、微小粒子を含む大気を流通させても長期間にわ
たって高い計測精度を維持する事ができる。According to the present invention, at least one of the valve body and the valve seat which comes into contact with or separates from each other is provided with a projection for always forming a gap between the valve body and the valve seat. So
Not only when the control valve is closed, but also when the mass flow rate is controlled by controlling the valve opening, fine particles flow into the valve chamber together with the atmosphere through the gap between the valve seat and the control valve, and further, the secondary flow path The fine particles do not accumulate in the valve chamber because they flow out to the next step through the valve. As a result, clogging does not occur, and high measurement accuracy can be maintained for a long period of time even when the atmosphere containing fine particles flows.
【図１】本考案の微小粒子を含む大気の測定方法のフロ
ー図FIG. 1 is a flowchart of the method for measuring the atmosphere containing fine particles according to the present invention.
【図２】一般的に使用される質量流量制御器の一実施例
の中央縦断面図FIG. 2 is a central longitudinal sectional view of one embodiment of a commonly used mass flow controller.
【図３】本考案のコントロールバルブ部の拡大中央縦断
面図FIG. 3 is an enlarged central longitudinal sectional view of the control valve portion of the present invention.
【図４】図３のコントロールバルブ部の要部拡大断面図FIG. 4 is an enlarged sectional view of a main part of the control valve unit of FIG. 3;
【図５】本考案の弁体の底面図FIG. 5 is a bottom view of the valve body of the present invention.
【図６】本考案の質量流量制御器の流量対差圧の関係を
表すグラフFIG. 6 is a graph showing the relationship between the flow rate and the differential pressure of the mass flow controller of the present invention.
【図７】従来例のコントロールバルブ部の目詰まり状態
を表す拡大中央縦断面図FIG. 7 is an enlarged central longitudinal sectional view showing a clogged state of a control valve section of a conventional example.
【図８】従来例の質量流量制御器の流量対差圧の関係を
表すグラフFIG. 8 is a graph showing a relationship between a flow rate and a differential pressure of a conventional mass flow controller.
(A)…質量流量制御器 (C)…センサ
部 (D)…バイパス部 (K)…間隙 (T)…突起 (3)…出口継
ぎ手 (12)(13)…流路 (16)…弁体 (18)…弁座 (CV)…制御弁(A)… Mass flow controller (C)… Sensor part (D)… Bypass part (K)… Gap (T)… Protrusion (3)… Outlet joint (12) (13)… Flow path (16)… Valve Body (18)… Valve seat (CV)… Control valve
Claims (1)
と、センサ部に流れる流体の流量に比例して流量が流れ
るバイパス部とを有し、バイパス部とセンサ部から流出
した流体が合流して外部装置に接続される出口継ぎ手に
連通せる流路に制御弁を設けた質量流量制御器におい
て、制御弁の互いに当接・離間する弁体と弁座の少なく
ともいずれか一方の当接面に弁体と弁座との間に間隙を
形成するための突起が突設されている事を特徴とする質
量流量制御器の制御弁構造。A sensor configured to measure a flow rate of the fluid; and a bypass section configured to flow in proportion to the flow rate of the fluid flowing through the sensor section. In a mass flow controller provided with a control valve in a flow path communicating with an outlet joint connected to an apparatus, a valve body is provided on at least one of a contact surface of a valve body and a valve seat that contact and separate from each other of the control valve. A control valve structure for a mass flow controller, characterized in that a projection for forming a gap is provided between the valve and a valve seat.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1992019018U JP2575685Y2 (en) | 1992-02-27 | 1992-02-27 | Control valve structure of mass flow controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1992019018U JP2575685Y2 (en) | 1992-02-27 | 1992-02-27 | Control valve structure of mass flow controller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0569477U JPH0569477U (en) | 1993-09-21 |
| JP2575685Y2 true JP2575685Y2 (en) | 1998-07-02 |
Family
ID=11987746
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1992019018U Expired - Lifetime JP2575685Y2 (en) | 1992-02-27 | 1992-02-27 | Control valve structure of mass flow controller |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2575685Y2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5243730U (en) * | 1975-09-25 | 1977-03-28 | ||
| JPH03166611A (en) * | 1989-11-27 | 1991-07-18 | Nec Corp | Mass flow rate controller |
-
1992
- 1992-02-27 JP JP1992019018U patent/JP2575685Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0569477U (en) | 1993-09-21 |
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