JPH0125295Y2 - - Google Patents
Info
- Publication number
- JPH0125295Y2 JPH0125295Y2 JP7089582U JP7089582U JPH0125295Y2 JP H0125295 Y2 JPH0125295 Y2 JP H0125295Y2 JP 7089582 U JP7089582 U JP 7089582U JP 7089582 U JP7089582 U JP 7089582U JP H0125295 Y2 JPH0125295 Y2 JP H0125295Y2
- Authority
- JP
- Japan
- Prior art keywords
- pipe
- temperature
- heater
- tube
- fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000012530 fluid Substances 0.000 claims description 20
- 229910052751 metal Inorganic materials 0.000 claims description 11
- 239000002184 metal Substances 0.000 claims description 11
- 230000007797 corrosion Effects 0.000 claims description 8
- 238000005260 corrosion Methods 0.000 claims description 8
- 239000010410 layer Substances 0.000 description 25
- 238000001514 detection method Methods 0.000 description 20
- 229910001220 stainless steel Inorganic materials 0.000 description 19
- 239000010935 stainless steel Substances 0.000 description 19
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 8
- 229910052802 copper Inorganic materials 0.000 description 8
- 239000010949 copper Substances 0.000 description 8
- 238000011144 upstream manufacturing Methods 0.000 description 7
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 6
- 229910052709 silver Inorganic materials 0.000 description 6
- 239000004332 silver Substances 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 230000002093 peripheral effect Effects 0.000 description 5
- 230000004044 response Effects 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000004043 responsiveness Effects 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- -1 which is expensive Chemical compound 0.000 description 1
Landscapes
- Measuring Volume Flow (AREA)
Description
【考案の詳細な説明】
第１図のように、流体（主として気体）が流れ
るパイプ１を、ヒータ４で流体の温度より高い温
度に加熱し、流れ方向にそつて一定の距離はなれ
た２点Ａ，Ｂの温度をセンサ５，６で測定して、
Ａ，Ｂ間の温度差ΔTを温度差検出器７にて測定
すると、パイプ内を流れる流体の質量流量Fmと
の間には略一定の関係が成立することがわかる。
この原理を用いた流量計は熱式質量流量計
（Thermal Mass Flow Meter）と呼ばれ、各種
のものが実用に供せられている。[Detailed description of the invention] As shown in Fig. 1, a pipe 1 through which a fluid (mainly gas) flows is heated by a heater 4 to a temperature higher than the temperature of the fluid, and two points are separated by a certain distance along the flow direction. Measure the temperatures of A and B with sensors 5 and 6,
When the temperature difference ΔT between A and B is measured by the temperature difference detector 7, it can be seen that a substantially constant relationship is established between the temperature difference ΔT and the mass flow rate Fm of the fluid flowing in the pipe.
Flow meters that use this principle are called thermal mass flow meters, and various types are in practical use.
この種の流量計を構造上大別すると、つぎの二
種になる。 This type of flow meter can be roughly divided into the following two types based on its structure.
すなわち、第一の形式は、第２図のように主パ
イプ１にある種の絞り部２を設け、絞りの前後に
入口、出口をもつパイパス管３を設け、バイパス
管に上記の加熱および温度差検出部を装備してバ
イパス管路の流量を検出し、あらかじめ求めたバ
イパス管と主パイプとの流量比から総流量を知る
方式である。 That is, in the first type, as shown in Fig. 2, a main pipe 1 is provided with a kind of constriction section 2, a bypass pipe 3 having an inlet and an outlet is provided before and after the constriction, and the bypass pipe is heated and heated as described above. This system is equipped with a difference detector to detect the flow rate in the bypass pipe, and determines the total flow rate from the predetermined flow rate ratio between the bypass pipe and the main pipe.
第二の形式は、バイパス部を設けず、第３図の
ように主パイプの流量を直接検出する方式であ
る。 The second type is a method in which a bypass section is not provided and the flow rate of the main pipe is directly detected as shown in FIG.
どちらの形式も流体の流路は金属管で構成さ
れ、通常は耐食性をもたせるためにステンレス網
のパイプが使用される。 In both types, the fluid flow path is constructed of metal pipes, usually stainless steel pipes for corrosion resistance.
この種の流量計の応答速度は、加熱および温度
差検出部の管長が短いほど、また管の温度伝導率
が大きいほど速くなる。 The response speed of this type of flowmeter becomes faster as the tube length of the heating and temperature difference detection section is shorter and as the temperature conductivity of the tube is greater.
一方、流速の検出感度、すなわち一定の流量に
おける温度差ΔTの大きさは、管長が長いほど、
また管の断面積（周長×肉厚）が小さいほど大き
く、流量の検出精度が高くなる。 On the other hand, the detection sensitivity of flow velocity, that is, the magnitude of temperature difference ΔT at a constant flow rate, increases as the pipe length increases.
Furthermore, the smaller the cross-sectional area (peripheral length x wall thickness) of the pipe, the greater the flow rate detection accuracy.
ステンレス銅は金属の中で最も温度伝導率が小
さいものの一つであるため、応答速度をあまり低
くせずに必要な流量検出感度を得るには、検出部
の管の径を小さく、かつ肉厚を薄くする必要があ
る。 Stainless copper has one of the lowest thermal conductivities of all metals, so in order to obtain the necessary flow rate detection sensitivity without reducing the response speed too much, the diameter of the tube in the detection section should be small and the wall should be thick. It is necessary to make it thinner.
一方、温度伝導率の大きい金属管を使用すれ
ば、管径、管の肉厚についてはステンレス綱より
もはるかに大きくしても性能上の問題はないが、
具体的材料としては金、白金などきわめて高価で
あるか、あるいは銀、銅、アルミニウムなど耐食
性に問題があるかの何れかであり、ステンレス綱
にくらべて実用的に問題が多い。 On the other hand, if a metal tube with high thermal conductivity is used, there will be no performance problem even if the tube diameter and wall thickness are much larger than that of stainless steel.
The specific materials are either extremely expensive, such as gold or platinum, or silver, copper, or aluminum, which have problems in corrosion resistance, and have more practical problems than stainless steel.
このような背景から現在実用に供せられている
熱式質量流量計の多くは、バイパス管にきわめて
小径のステンレス綱のパイプを使用した第２図の
タイプである。 Against this background, most of the thermal mass flowmeters currently in practical use are of the type shown in FIG. 2, which uses an extremely small diameter stainless steel pipe as the bypass pipe.
しかし、この種の極細バイパス管を使用したも
のは、流体の結露やダストにより管が閉塞し、作
動不良になりやすく、この面での改良が望まれて
いる。管の閉塞を防止するために、管の径をある
程度大きくし、きわめて肉の薄いパイプを使用し
たものも存在はするが、耐圧が低く、また強度上
の信頼性にも問題がある。 However, devices using this type of ultra-thin bypass pipe tend to become clogged due to fluid condensation or dust, resulting in malfunction, and improvements in this aspect are desired. In order to prevent the pipe from clogging, there are some pipes in which the diameter of the pipe is increased to a certain extent and the pipe is made of extremely thin wall, but these have low pressure resistance and have problems with reliability in terms of strength.
また、銅系のパイプを使用したものの例もある
が、耐食上の問題で使用できる流体が制限され
る。 There are also examples that use copper-based pipes, but the fluids that can be used are limited due to corrosion resistance issues.
そこで、本考案は特殊な検熱パイプを使用する
ことにより、現在実用に供せられている熱式質量
流量計の欠点を改善し、下記の諸条件を満たし得
る熱式流量計を提供できるようにした。 Therefore, by using a special heat-detecting pipe, the present invention improves the shortcomings of the thermal mass flowmeters currently in practical use and provides a thermal mass flowmeter that satisfies the following conditions. I made it.
検出部の管径をある程度大きく、管の閉塞が
生じにくいこと。 The tube diameter of the detection part should be increased to a certain extent so that blockage of the tube is less likely to occur.
応答性、流量検出感度が実用上許容できるレ
ベルにあること。 Responsiveness and flow rate detection sensitivity must be at a practically acceptable level.
流体に接する部分の材質はステンレス綱また
はこれ以上の耐食性をもつこと。 The material of the parts that come into contact with the fluid must be stainless steel or more corrosion resistant.
管の耐圧、強度は広い実用条件に適応可能な
こと。 The pressure resistance and strength of the pipe must be adaptable to a wide range of practical conditions.
従来のものにくらべ著しくコスト高になるも
のでないこと。 The cost should not be significantly higher than conventional ones.
前記の条件を満たすには、ステンレス綱と同等
の耐食性、強度を有し、かつ温度伝導率の高いパ
イプを検出部に使用することができればよい。 In order to satisfy the above conditions, it is sufficient to use a pipe in the detection section that has corrosion resistance and strength equivalent to stainless steel and has high thermal conductivity.
よつて、本考案に係る熱式質量流量計は、ヒー
タを備えていて、このヒータを挟む２点に温度セ
ンサを配したパイプ内を流体が流れ、かつ前記２
点の各温度の差を検出して流体の質量流量を測定
する熱式流量計において、前記パイプを、内層の
ものが耐蝕性に富むとともに耐圧強度を有し、外
層のものが温度伝導率の高い金属製のものよりな
る複層管にて構成したことを特徴とするものとし
てある。 Therefore, the thermal mass flowmeter according to the present invention is equipped with a heater, and a fluid flows through a pipe in which temperature sensors are arranged at two points sandwiching the heater, and
In a thermal flow meter that measures the mass flow rate of a fluid by detecting the difference in temperature at each point, the pipe has an inner layer that is highly corrosion resistant and has high pressure resistance, and an outer layer that has a high temperature conductivity. It is characterized by being constructed from a multi-layered pipe made of high-quality metal.
かくすることにより、ヒータからパイプに与え
られた熱は温度伝導率の高い外層を伝播し、広域
に渡つて内層をその外周面から加熱することがで
きる。 By doing so, the heat applied to the pipe from the heater propagates through the outer layer having high thermal conductivity, and the inner layer can be heated over a wide area from its outer peripheral surface.
本考案の熱式質量流量計の実施例は、検出部た
る第２図のバイパス管３又は第３図の主管１に第
４図のごとき検熱パイプ１１を用いたもので、こ
の検熱パイプ１１は例えば耐蝕性に富むステンレ
ス層１１ａの外周に温度伝導率の高い金属の層１
１ｂを形成させた多層管としてある。 An embodiment of the thermal mass flowmeter of the present invention uses a heat detection pipe 11 as shown in FIG. 4 in the bypass pipe 3 in FIG. 2 or the main pipe 1 in FIG. For example, 11 is a metal layer 1 with high temperature conductivity on the outer periphery of a stainless steel layer 11a with high corrosion resistance.
1b is formed as a multilayer tube.
検熱パイプの外層たる温度伝導率の高い金属の
層１１ｂは、内層たるステンレス層１１ａに直接
密着していることが望ましいので、メツキ、容
射、蒸着などの方法で、例えば極めて温度伝導率
の高い銀や、内層への接合が容易で低コストの銅
などをステンレス層１１ｂの外周面に直接接合さ
せる。 It is desirable that the metal layer 11b, which is the outer layer of the heat detection pipe, has a high temperature conductivity and is in direct contact with the stainless steel layer 11a, which is the inner layer. Silver, which is expensive, or copper, which is easy to bond to the inner layer and is low cost, is directly bonded to the outer peripheral surface of the stainless steel layer 11b.
上記のように構成した熱式質量流量計において
質量流量の計測を開始すると、検熱管１１がヒー
タ４によつて加熱され、さらに管内を流れる流体
を加熱する。 When the thermal mass flowmeter configured as described above starts measuring the mass flow rate, the heat detection tube 11 is heated by the heater 4, which further heats the fluid flowing inside the tube.
ここで、ヒータ４よりも上流における検熱管内
面から流体へ移動する熱量は大であるのに対し、
ヒータ４よりも下流における検熱管内面から、あ
る程度加熱された流体へ移動する熱量は小となる
ので、ヒータ４の適宜上流に配した温度センサ５
の検出値とヒータ４の適宜下流に配した温度セン
サ６の検出値には差異が生じ、この温度差ΔTは
温度差検出器７によつて検出される。 Here, while the amount of heat transferred from the inner surface of the thermometer tube to the fluid upstream of the heater 4 is large,
Since the amount of heat transferred from the inner surface of the thermometer tube downstream of the heater 4 to the fluid that has been heated to a certain extent is small, the temperature sensor 5 is placed appropriately upstream of the heater 4.
A difference occurs between the detected value of the temperature sensor 6 and the detected value of the temperature sensor 6 disposed appropriately downstream of the heater 4, and this temperature difference ΔT is detected by the temperature difference detector 7.
そして、ヒータ４による加熱開始後、適宜時間
が経過すると、検熱管各部の保有熱量と検熱管各
部から管内の流体へ移動する熱量が平衡点に達
し、検熱管各部の温度は平衡温度となる。 Then, after an appropriate amount of time has passed after the heater 4 starts heating, the amount of heat held in each part of the heat detection tube and the amount of heat transferred from each part of the heat detection tube to the fluid in the tube reach an equilibrium point, and the temperature of each part of the heat detection tube becomes the equilibrium temperature.
この検熱管各部の平衡温度はヒータ４の加熱量
及び流体の比熱と流量によつて特定されるので、
ヒータ４の上下流適所に配した温度センサ５，６
の検出温度から温度差検出器７の検出した温度差
ΔTによつて流体の質量流量を計出する。 The equilibrium temperature of each part of the thermometer tube is determined by the heating amount of the heater 4 and the specific heat and flow rate of the fluid.
Temperature sensors 5 and 6 placed at appropriate locations upstream and downstream of the heater 4
The mass flow rate of the fluid is calculated based on the temperature difference ΔT detected by the temperature difference detector 7 from the detected temperature.
しかして、検熱パイプ１１は内層たるステンレ
ス層１１ａの外周に温度伝導率の高い金属層１１
ｂを形成させてあるので、ヒータ４から検熱パイ
プ１１に与えられた熱は温度伝導率の高い金属層
１１ｂを伝播してヒータ４の上下流部分のステン
レス層を外周面から加熱し、検熱パイプの温度上
昇を促す。 Therefore, the heat detection pipe 11 has a metal layer 11 with high temperature conductivity on the outer periphery of the inner stainless steel layer 11a.
b is formed, the heat given to the heat detection pipe 11 from the heater 4 propagates through the metal layer 11b with high temperature conductivity, heats the stainless steel layers upstream and downstream of the heater 4 from the outer peripheral surface, and performs the test. Promotes temperature rise in heat pipes.
したがつて、ヒータ４付近の検熱管が平衡温度
に達して、一定の熱量が流体へ移動するようにな
つた後に、ヒータ４の上下流への熱伝播が始まる
単層の検熱管に比して検熱管各部が平衡温度に達
するまでに流体へ移動する熱量を可及的小ならし
め、検熱管１１の温度センサ５，６を配した部分
の温度が平衡温度に達するのに要する時間を極く
短いものとなし得る。 Therefore, compared to a single-layer thermometer tube, heat propagation begins upstream and downstream of the heater 4 after the thermometer tube near the heater 4 reaches an equilibrium temperature and a certain amount of heat begins to transfer to the fluid. The amount of heat transferred to the fluid until each part of the thermometer tube reaches the equilibrium temperature is minimized, and the time required for the temperature of the portion of the thermometer tube 11 where the temperature sensors 5 and 6 are arranged to reach the equilibrium temperature is minimized. It can be made very short.
また、第５図のごとくステンレスパイプ１１ａ
の外側に接合の容易な銅１１ｃの薄膜を例えばメ
ツキし、さらにこの銅１１ｃの外側に銀１１ｄを
例えばメツキした３層構造のものとしても、前述
したと同様に、検熱管１１の温度センサ５，６を
配した部分の温度が平衡温度に達する時間を極く
短いものとなし得る。 Also, as shown in Fig. 5, the stainless steel pipe 11a
The temperature sensor 5 of the thermometer tube 11 may be of a three-layer structure, in which a thin film of copper 11c, which is easy to bond, is plated on the outside of the copper 11c, and silver 11d is further plated on the outside of the copper 11c, as described above. , 6 can be arranged in a very short time for the temperature to reach the equilibrium temperature.
第６図は多層管を使用した場合の応答性改善の
効果をステンレスパイプの場合と比較した結果の
一例である。 FIG. 6 is an example of the results of comparing the response improvement effect when using a multilayer pipe with that when using a stainless steel pipe.
流速０の状態から急に管内に一定流量の流れが
生じたとき、検出部の二点Ａ，Ｂ間の温度差が時
間とともにどのように変化するかを示したグラフ
で、ステンレスパイプでは真の流量に対応する温
度差に達するのに４分を要するのに対し、外層を
銀とした多層管ではわずか15秒となつた。 This is a graph showing how the temperature difference between two points A and B of the detection section changes over time when a constant flow rate suddenly occurs in the pipe from a state of zero flow rate. It took four minutes to reach the temperature difference corresponding to the flow rate, whereas it took only 15 seconds for the multilayer tube with a silver outer layer.
なお、この実験に使用した多層管は、内径が
1.8mm、外径が2.0mm、長さが100mmのステンレス
管の表面へ30μmの銀メツキを施したものであり、
単層ステンレス管は、内径が1.8mm、外径が2.0
mm、長さが100mmのものである。 Note that the inner diameter of the multilayer tube used in this experiment is
It is a stainless steel tube with a diameter of 1.8 mm, an outer diameter of 2.0 mm, and a length of 100 mm, with 30 μm silver plating applied to the surface.
Single layer stainless steel pipe has an inner diameter of 1.8mm and an outer diameter of 2.0mm.
mm, and the length is 100 mm.
以上説明したように、本考案に係る熱式質量流
量計によれば、ヒータから検熱管に与えられる熱
を、ステンレス層の外周に形成した温度伝導率の
高い金属層から上下流方向に伝播させ、温度伝導
率の低いステンレス層をその外周面から加熱する
ので、ヒータによる局部加熱を疑似的な広域加熱
となし得る。 As explained above, according to the thermal mass flowmeter according to the present invention, the heat given from the heater to the thermometer tube is propagated in the upstream and downstream directions from the metal layer with high thermal conductivity formed around the outer periphery of the stainless steel layer. Since the stainless steel layer, which has low thermal conductivity, is heated from its outer peripheral surface, local heating by the heater can be turned into pseudo-wide-area heating.
したがつて、検熱管各部の温度が平衡温度に達
する前に流体へ移動して失われる熱量を可及的小
ならしめ、極く短時間で検熱管各部が平衡温度に
達するので、計測を開始してヒータの適宜上下流
に配した温度センサ５，６によつて温度検出器が
温度差ΔTを検出するまでに要する時間を短時間
に止め、流量計の応答性を著しく向上できる。 Therefore, the amount of heat transferred to the fluid and lost before the temperature of each part of the thermometer tube reaches the equilibrium temperature is minimized, and each part of the thermometer tube reaches the equilibrium temperature in a very short time, so measurement can be started. By using the temperature sensors 5 and 6 placed upstream and downstream of the heater, the time required for the temperature detector to detect the temperature difference ΔT can be shortened, and the responsiveness of the flowmeter can be significantly improved.
なお、第６図において多層管の温度差がステン
レス管の温度差ほど上昇しないのは、温度伝導率
の高い検熱管の外層から検熱管外へ熱が放出され
るためであるが、検熱管の外径、外層の厚さ、温
度センサの配設位置を適宜選定することで、十分
な精度の計測値を計出するに足る温度差ΔTを得
ることができる。 The reason why the temperature difference in the multilayer tube does not increase as much as the temperature difference in the stainless steel tube in Figure 6 is that heat is released from the outer layer of the thermometer tube, which has high thermal conductivity, to the outside of the thermometer tube. By appropriately selecting the outer diameter, the thickness of the outer layer, and the location of the temperature sensor, it is possible to obtain a temperature difference ΔT sufficient to calculate a measurement value with sufficient accuracy.
第１図乃至第３図は従来の熱式質量流量計を示
す図、第４図は本考案における検熱パイプの断面
図、第５図は同検熱パイプの他の実施例を示す断
面図、第６図は温度差と応答時間の関係を示すグ
ラフである。
図中、１……主パイプ、２……絞り部、３……
バイパス管、４……ヒータ、５，６……温度セン
サ、７……温度差検出器、１１……検熱パイプ、
１１ａ……ステンレス層、１１ｂ……温度伝導率
の高い金属層、１１ｃ……銅、１１ｄ……銀。
Figures 1 to 3 are diagrams showing a conventional thermal mass flowmeter, Figure 4 is a sectional view of a heat detection pipe according to the present invention, and Figure 5 is a sectional view showing another embodiment of the heat detection pipe. , FIG. 6 is a graph showing the relationship between temperature difference and response time. In the figure, 1...main pipe, 2...throttle section, 3...
Bypass pipe, 4... Heater, 5, 6... Temperature sensor, 7... Temperature difference detector, 11... Heat detection pipe,
11a...Stainless steel layer, 11b...Metal layer with high temperature conductivity, 11c...Copper, 11d...Silver.
Claims (1)
温度センサを配したパイプ内を流体が流れ、かつ
前記２点の各温度の差を検出して流体の質量流量
を測定する熱式流量計において、前記パイプを、
内層のものが耐蝕性に富むとともに耐圧強度を有
し、外層のものが温度伝導率の高い金属製のもの
よりなる複層管にて構成したことを特徴とする熱
式質量流量計。 In a thermal flowmeter that is equipped with a heater, and in which fluid flows through a pipe with temperature sensors placed at two points sandwiching the heater, and the mass flow rate of the fluid is measured by detecting the difference in temperature between the two points. , the pipe,
A thermal mass flowmeter characterized in that the inner layer is highly corrosion resistant and has high pressure resistance, and the outer layer is made of a multilayer tube made of metal with high thermal conductivity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7089582U JPS58172819U (en) | 1982-05-14 | 1982-05-14 | Thermal mass flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7089582U JPS58172819U (en) | 1982-05-14 | 1982-05-14 | Thermal mass flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58172819U JPS58172819U (en) | 1983-11-18 |
| JPH0125295Y2 true JPH0125295Y2 (en) | 1989-07-28 |
Family
ID=30080537
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7089582U Granted JPS58172819U (en) | 1982-05-14 | 1982-05-14 | Thermal mass flow meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58172819U (en) |
-
1982
- 1982-05-14 JP JP7089582U patent/JPS58172819U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58172819U (en) | 1983-11-18 |
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