JPS635694B2 - - Google Patents
Info
- Publication number
- JPS635694B2 JPS635694B2 JP57049266A JP4926682A JPS635694B2 JP S635694 B2 JPS635694 B2 JP S635694B2 JP 57049266 A JP57049266 A JP 57049266A JP 4926682 A JP4926682 A JP 4926682A JP S635694 B2 JPS635694 B2 JP S635694B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- density
- vapor
- pressure
- steam
- 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
- 229920006395 saturated elastomer Polymers 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 12
- 238000010586 diagram Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 2
- 238000007619 statistical method Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Description
【発明の詳細な説明】
本発明は、温度及び圧力を測定することにより
正確な蒸気密度を測定することができる蒸気密度
測定方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring vapor density that can accurately measure vapor density by measuring temperature and pressure.
一般に、気体流量の測定を行う場合、その温度
補正はボイルシヤールの法則を用いて行うことが
できる。しかしながら、蒸気の性質は完全気体の
ように単純でなく、簡単な式で表わすことは不可
能である。蒸気の場合、大きな過熱領域では蒸気
密度は温度に逆比例、圧力に比例するので、温度
及び圧力から蒸気密度を算出することができる。
しかし、蒸気の温度が飽和温度に近いところで
は、温度、圧力対蒸気密度の特性が曲線となり単
純に１次式で蒸気密度を算出することはできな
い。 Generally, when measuring a gas flow rate, temperature correction can be performed using Boilschard's law. However, the properties of vapor are not as simple as those of a perfect gas, and cannot be expressed using a simple equation. In the case of steam, steam density is inversely proportional to temperature and proportional to pressure in large superheated regions, so steam density can be calculated from temperature and pressure.
However, where the temperature of the steam is close to the saturation temperature, the characteristics of temperature and pressure vs. steam density become a curve, making it impossible to simply calculate the steam density using a linear equation.
本発明は、このような点に鑑みてなされたもの
で、蒸気密度ｙを圧力ｘの１次式としてｙ＝ax
＋ｂ（ａ、ｂは定数）と近似できる領域で、蒸気
密度表から各温度における最適な定数ａ、ｂを温
度の関数として記憶しておき、各温度における最
適な定数ａ、ｂを上式に与えるようにして、正確
な蒸気密度を測定することのできる方法を実現し
たものである。以下、図面を参図して本発明を詳
細に説明する。 The present invention has been made in view of these points, and the present invention is based on the equation y = ax where the vapor density y is a linear expression of the pressure x.
In the region that can be approximated as This method has realized a method that can accurately measure vapor density by giving the following information. Hereinafter, the present invention will be explained in detail with reference to the drawings.
第１図は、蒸気密度特性を示す図である。縦軸
ｙは蒸気密度（単位Kg／m3）を、横軸ｘは圧力
（単位Kg／cm2Ｇ、Ｇ……ゲージ圧）を示す。図中、
f1は飽和蒸気の特性、f2は温度T1における、f3は
温度T2における、f4は温度T3におけるそれぞれ
密度特性を示す図である。但しT1＜T2＜T3であ
る。図より、圧力ｘが比較的高い領域では密度ｙ
は１次式で近似しても十分正確な値が得られるこ
とがわかる。また、全ての曲線が圧力ｘが上がる
と飽和蒸気曲線f1とぶつかることがわかる。前述
したように、ｘが比較的高い領域では単純な１次
式で密度ｙを求めることができる。ａ、ｂを算出
する過程を、以下に説明する。先ず、各温度ごと
における蒸気密度ｙを圧力ｘを従属変数としてプ
ロツトする。プロツトする温度幅は例えば10℃間
隔程度である。プロツトするための基礎データ
は、例えば日本機会学会より公表されている蒸気
密度表を利用する。以上の操作を行うと、各温度
ごとの圧力ｘに対する蒸気密度ｙの分布が第２図
に示すように得られる。この分布図は説明の便宜
のために簡略化してある。このようにして得られ
る各分布点y1，y2，……からの距離がそれぞれ最
も小さくなるような直線ｌを引くことを考える。
測定誤差を問題にしなければ、目算で引くことも
できるが、通常は統計的手法を用いる。 FIG. 1 is a diagram showing vapor density characteristics. The vertical axis y indicates the vapor density (unit Kg/m 3 ), and the horizontal axis x indicates the pressure (unit Kg/cm 2 G, G...gauge pressure). In the figure,
1 is a diagram showing the characteristics of saturated steam, f 2 the density characteristics at temperature T 1 , f 3 at temperature T 2 , and f 4 at temperature T 3, respectively. However, T 1 < T 2 < T 3 . From the figure, in the region where the pressure x is relatively high, the density y
It can be seen that a sufficiently accurate value can be obtained even when approximated by a linear equation. It can also be seen that all the curves collide with the saturated vapor curve f 1 as the pressure x increases. As mentioned above, in a region where x is relatively high, the density y can be determined using a simple linear equation. The process of calculating a and b will be explained below. First, the vapor density y at each temperature is plotted with the pressure x as the dependent variable. The temperature range to be plotted is, for example, about 10°C. The basic data for plotting is, for example, the vapor density table published by the Japan Society of Mechanical Engineers. By carrying out the above operations, a distribution of vapor density y with respect to pressure x at each temperature is obtained as shown in FIG. This distribution diagram is simplified for convenience of explanation. Consider drawing a straight line l that minimizes the distance from each of the distribution points y 1 , y 2 , . . . obtained in this way.
If measurement error is not an issue, it can be calculated by estimation, but statistical methods are usually used.
統計的手法としては、例えば最小２乗法等が用
いられる。このような方法により求めた直線ｌの
定数ａ、ｂを各温度ごとにプロツトすると第３図
に示すようなものとなる。同図イは定数ａを、同
図ロは定数ｂをそれぞれ示している。横軸Ｔは何
れも温度を示す。第３図に示すような特性を、予
め記憶しておく。記憶方法としては、例えば折線
で近似して折線関数として記憶しておく方法や、
算出データをそのまま内蔵のメモリ（例えば
ROM）に記憶しておく方法等が考えられる。 As a statistical method, for example, the method of least squares is used. When the constants a and b of the straight line l obtained by this method are plotted at each temperature, the result is as shown in FIG. Figure A shows the constant a, and Figure B shows the constant b. The horizontal axis T indicates temperature. Characteristics as shown in FIG. 3 are stored in advance. Examples of storage methods include, for example, approximating it with a broken line and storing it as a broken line function;
The calculated data can be stored directly in the built-in memory (e.g.
One possible method is to store it in a ROM).
このように、定数ａ、ｂを温度の関数として記
憶しておけば、必要に応じて定数ａ、ｂを取出す
ことができる。例えば、蒸気温度がT1であつた
とすると、対応する定数a1、b1が取出せる。次
に、圧力x1を測定によつて求めると、そのときの
蒸気密度y1は、y1＝a1x1＋b1として計算により求
めることができる。各温度ごとに求められた定数
ａ、ｂは、全ての圧力範囲について決定された値
であるので、第１図の圧力ｘが小さい非直線領域
についても同様に適用することができる。そし
て、ｘが小さい場合でも満足すべき値ｙを与え
る。なお、蒸気が過熱蒸気の場合は上述の方法に
よつて算出した蒸気密度をそのまま用いることが
できるが、圧力ｘが高くなつて飽和蒸気曲線f1と
ぶつかつた後は、全ての圧力に対してf1について
定まつた定数ａ、ｂを用いるようにする必要があ
る。曲線f2（第１図参照）について説明すると、
f2がf1とぶつかる点Ａまでが過熱蒸気領域で、Ａ
より圧力の大きい領域は飽和蒸気領域である。過
熱蒸気領域の任意の温度T1圧力x1における蒸気
密度をy1、飽和蒸気領域内の温度T1′圧力x2にお
ける密度をy2とするとそれぞれの蒸気密度は次式
のように表わされる。 By storing the constants a and b as functions of temperature in this way, the constants a and b can be extracted as needed. For example, if the steam temperature is T 1 , the corresponding constants a 1 and b 1 can be extracted. Next, when the pressure x 1 is determined by measurement, the vapor density y 1 at that time can be determined by calculation as y 1 =a 1 x 1 +b 1 . Since the constants a and b determined for each temperature are values determined for all pressure ranges, they can be similarly applied to the non-linear region where the pressure x is small in FIG. Then, even if x is small, a satisfactory value y is given. Note that if the steam is superheated steam, the steam density calculated by the above method can be used as is, but after the pressure x increases and collides with the saturated steam curve f 1 , It is necessary to use constants a and b determined for f1 . To explain the curve f 2 (see Figure 1),
The area up to point A where f 2 collides with f 1 is the superheated steam region, and A
The region of higher pressure is the saturated steam region. Let y 1 be the steam density at any temperature T 1 and pressure x 1 in the superheated steam region, and y 2 be the density at temperature T 1 'pressure x 2 in the saturated steam region.The respective steam densities are expressed as follows. .
y1＝a1x1＋b1 (1)
y2＝a2x2＋b2 (2)
(2)式における定数a2、b2は飽和蒸気曲線f1につ
いての定数で温度に関係なく一定である。飽和蒸
気領域については、第３図に示す定数ａ、ｂを用
いることはできない。 y 1 = a 1 x 1 + b 1 (1) y 2 = a 2 x 2 + b 2 (2) The constants a 2 and b 2 in equation (2) are constants for the saturated vapor curve f 1 and are constant regardless of temperature. It is. For the saturated steam region, constants a and b shown in FIG. 3 cannot be used.
第４図は、本発明を実施するための蒸気密度測
定装置の一実施例を示す電気的構成図である。図
において、１はその中を蒸気が流れる蒸気配管、
２は蒸気温度を検出する温度検出器、３は蒸気圧
力を検出する圧力検出器である。４，５は温度検
出器２の出力を受けて温度を指示する温度指示
計、６は圧力検出器３の出力を受けて圧力を指示
する圧力指示計である。７は定数ａを温度の関数
として記憶しておき温度指示計４の出力に応じた
値を出力する第１の演算器、８は定数ｂの温度の
関数として記憶しておき温度指示計５の出力に応
じた値を出力する第２の演算器である。 FIG. 4 is an electrical configuration diagram showing an embodiment of a vapor density measuring device for carrying out the present invention. In the figure, 1 is a steam pipe through which steam flows;
2 is a temperature detector for detecting steam temperature, and 3 is a pressure detector for detecting steam pressure. 4 and 5 are temperature indicators that receive the output from the temperature detector 2 and indicate the temperature, and 6 is a pressure indicator that receives the output from the pressure detector 3 and indicates the pressure. 7 is a first computing unit that stores constant a as a function of temperature and outputs a value corresponding to the output of temperature indicator 4; 8 stores constant b as a function of temperature and outputs a value corresponding to the output of temperature indicator 5; This is a second arithmetic unit that outputs a value according to the output.
９は定数ａの指示計、１０は定数ｂの指示計で
ある。１１は演算器７，８の出力ａ，ｂ及び圧力
指示計６の出力ｘを受けてｙ＝ax＋ｂを演算す
ることにより過熱蒸気領域における蒸気密度を算
出する第３の演算器、１２は飽和蒸気領域におい
て圧力指示計６の出力を受けて対応する飽和蒸気
密度を算出する第４の演算器である。１３は、演
算器１１，１２の出力を比較し、演算器１１の出
力が大きい場合、演算器１２側に切換えて出力
し、演算器１１の出力が小さい場合、演算器１１
側に切換えて出力する切換器、１４は指示計であ
る。切換器１３から蒸気密度ｙが出力される。こ
のような装置によつて蒸気密度ｙが算出される
と、蒸気重量流量Ｗはオリフイスの設計基準密度
をrBとして次式によつて求めることができる。 9 is an indicator with a constant a, and 10 is an indicator with a constant b. 11 is a third computing unit which calculates the steam density in the superheated steam region by receiving the outputs a, b of the computing units 7 and 8 and the output x of the pressure indicator 6 and calculating y=ax+b; 12 is the saturated steam This is a fourth computing unit that receives the output of the pressure indicator 6 in the region and calculates the corresponding saturated vapor density. 13 compares the outputs of the arithmetic units 11 and 12, and when the output of the arithmetic unit 11 is large, the output is switched to the arithmetic unit 12 side, and when the output of the arithmetic unit 11 is small, the output is switched to the arithmetic unit 12 side.
14 is an indicator which switches to the side and outputs the output. The switching device 13 outputs the vapor density y. When the steam density y is calculated by such a device, the steam weight flow rate W can be determined by the following equation, where r B is the design standard density of the orifice.
Wbp：補正前流量（Kg／ｈ）
以上、詳細に説明したように、本発明によれば
蒸気密度ｙを圧力ｘの１次式ｙ＝ax＋ｂ（ａ、ｂ
は定数）と近似できる領域で、蒸気密度表から各
温度における最適な定数ａ、ｂを温度の関数とし
て記憶しておき、各温度における最適な定数ａ、
ｂを上式に与えるようにして正確な蒸気密度を測
定することができる蒸気密度測定方法を実現する
ことができる。 W bp : Pre-correction flow rate (Kg/h) As explained above in detail, according to the present invention, the vapor density y is calculated using the linear equation y=ax+b(a, b
is a constant), and the optimum constants a and b at each temperature are memorized from the vapor density table as a function of temperature, and the optimum constants a and b at each temperature are calculated from the vapor density table.
By giving b to the above equation, it is possible to realize a vapor density measuring method that can accurately measure vapor density.
第１図、第２図は密度特性を示す図、第３図は
定数ａ，ｂの特性を示す図、第４図は本発明を実
施するための蒸気密度測定装置の一実施例を示す
電気的構成図である。
１……蒸気配管、２……温度検出器、３……圧
力検出器、４，５……温度指示計、７，８，１
１，１２……演算器、９，１０……定数指示計、
１３……切換器、１４……密度指示計。
Figures 1 and 2 are diagrams showing density characteristics, Figure 3 is a diagram showing characteristics of constants a and b, and Figure 4 is an electrical diagram showing an embodiment of a vapor density measuring device for carrying out the present invention. It is a configuration diagram. 1... Steam piping, 2... Temperature detector, 3... Pressure detector, 4, 5... Temperature indicator, 7, 8, 1
1, 12... Arithmetic unit, 9, 10... Constant indicator,
13...Switcher, 14...Density indicator.
Claims (1)
蒸気密度を測定する蒸気密度測定方法で下記ａ乃
至ｄの工程を行うことを特徴とする蒸気密度測定
方法。 ａ 過熱蒸気領域における、各温度毎の圧力と蒸
気密度との直線近似式の定数を温度の関数とし
て記憶する工程 ｂ 前記蒸気温度に基づき前記定数を取出し、前
記直線近似式を特定し、この式に前記蒸気圧力
を与えて蒸気密度を算出する工程 ｃ 飽和蒸気領域における圧力と蒸気密度との関
係式に基づき、前記蒸気圧力から飽和蒸気密度
を算出する工程 ｄ 前記ｂの工程で算出した蒸気密度と前記ｃの
工程で算出した飽和蒸気密度とを比較し、前記
飽和蒸気密度より小さいとき前記ｂの工程で算
出した蒸気密度を出力し、前記飽和蒸気密度よ
り大きいときこの飽和蒸気密度を出力する工
程。[Scope of Claims] 1. A vapor density measuring method for measuring vapor density by measuring vapor temperature and vapor pressure, characterized in that the following steps a to d are performed. a Step of storing the constant of the linear approximation formula between pressure and steam density for each temperature in the superheated steam region as a function of temperature b Extracting the constant based on the steam temperature, specifying the linear approximation formula, and converting this formula into Step c of calculating the vapor density by giving the vapor pressure to Step c Calculating the saturated vapor density from the vapor pressure based on the relational expression between pressure and vapor density in the saturated vapor region Vapor density calculated in step b above and the saturated vapor density calculated in step c, and when it is smaller than the saturated vapor density, output the vapor density calculated in step b, and when it is larger than the saturated vapor density, output this saturated vapor density. Process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4926682A JPS58166242A (en) | 1982-03-26 | 1982-03-26 | Measuring method of vapor density |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4926682A JPS58166242A (en) | 1982-03-26 | 1982-03-26 | Measuring method of vapor density |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58166242A JPS58166242A (en) | 1983-10-01 |
| JPS635694B2 true JPS635694B2 (en) | 1988-02-04 |
Family
ID=12826024
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4926682A Granted JPS58166242A (en) | 1982-03-26 | 1982-03-26 | Measuring method of vapor density |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58166242A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63206634A (en) * | 1987-02-24 | 1988-08-25 | Toshiba Corp | Gas density sensor |
| JP5964228B2 (en) * | 2012-02-22 | 2016-08-03 | 三菱重工業株式会社 | Steam table value calculation system, steam table value calculation method and control device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5649938A (en) * | 1979-09-29 | 1981-05-06 | Shimadzu Corp | Measuring device for specific volume of superheated vapor |
-
1982
- 1982-03-26 JP JP4926682A patent/JPS58166242A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5649938A (en) * | 1979-09-29 | 1981-05-06 | Shimadzu Corp | Measuring device for specific volume of superheated vapor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58166242A (en) | 1983-10-01 |
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