JPH02201225A - Differential pressure type measuring apparatus - Google Patents
Differential pressure type measuring apparatusInfo
- Publication number
- JPH02201225A JPH02201225A JP2194389A JP2194389A JPH02201225A JP H02201225 A JPH02201225 A JP H02201225A JP 2194389 A JP2194389 A JP 2194389A JP 2194389 A JP2194389 A JP 2194389A JP H02201225 A JPH02201225 A JP H02201225A
- Authority
- JP
- Japan
- Prior art keywords
- liquid
- pressure
- density
- differential pressure
- storage tank
- 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.)
- Granted
Links
Landscapes
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は差圧計を用いて被測定液の液面高さや密度を計
測する差圧式計測装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a differential pressure measuring device that measures the liquid level and density of a liquid to be measured using a differential pressure gauge.
従来より差圧計−を用いた液面計や密度計が知られてお
り、このような差圧計を利用した計測装置としては、例
えば、特開昭61−100618号公報等に提案されて
いる。Liquid level gauges and density meters using differential pressure gauges have been known in the past, and measuring devices using such differential pressure gauges have been proposed, for example, in Japanese Patent Laid-Open No. 100618/1983.
その基本原理を第4図に示すと、まず、第1の圧力入力
部1aと第2の圧力入力部1bを有しこれら各圧力入力
部(1a、1b)に入力される圧力の差圧を測定する差
圧計1を備えている。The basic principle is shown in FIG. 4. First, it has a first pressure input section 1a and a second pressure input section 1b, and the differential pressure between the pressures input to each of these pressure input sections (1a, 1b) is calculated. It is equipped with a differential pressure gauge 1 for measurement.
そして、差圧計1の第1の圧力入力部1aが第1の管3
で被測定液を収容した貯溜2に接続されるとともに、差
圧計1の第2の圧力入力部1bが第2の管4で貯溜2に
接続され、かつ、第2の管4と貯溜2との接続点は第1
の管3と貯溜2との接続点よりも高い位置にある。The first pressure input part 1a of the differential pressure gauge 1 is connected to the first pipe 3.
The second pressure input section 1b of the differential pressure gauge 1 is connected to the reservoir 2 through the second pipe 4, and the second pipe 4 and the reservoir 2 are connected to each other through the second pipe 4. The connection point is the first
It is located at a higher position than the connection point between the pipe 3 and the reservoir 2.
さらに、第1及び第2の管4内にシール液が充填され、
この第1の圧力入力部1aに入力される圧力(P++ρ
dH)(P+=貯漕回漕内圧d=被測定液の密度、H=
第1の圧力入力部1aから被測定液面までの高さ)と第
2の圧力入力部1bに入力される圧力(P++ρ5h)
(ρ5=シール液の密度、h=第2の圧力入力部1bか
ら起算したシール液の封入高さ)とから両者の差圧を検
出する差圧検出手段13を備えている。Furthermore, the first and second tubes 4 are filled with sealing liquid,
The pressure (P++ρ
dH) (P+ = Storage tank internal pressure d = Density of the liquid to be measured, H =
height from the first pressure input section 1a to the measured liquid level) and the pressure input to the second pressure input section 1b (P++ρ5h)
(ρ5=density of the sealing liquid, h=filling height of the sealing liquid calculated from the second pressure input section 1b).
乙のような装置では、差圧△Pを検出するにあたり、次
の式
%式%)
において、当初H=0とし、あらかじめ上式右辺にρ、
hを加えることによりΔP=Oに調整(ゼロ点調整)し
てから測定を開始する。In a device like B, to detect the differential pressure △P, use the following formula (% formula %), initially set H = 0, and preset ρ, ρ, on the right side of the above formula.
Measurement is started after adjusting ΔP=O by adding h (zero point adjustment).
しかし、ゼロ点調整時と使用時とに温度差があると、シ
ール液密度が温度変化に伴って変化するため、ゼロ点が
移動し、誤差を生じる。However, if there is a temperature difference between the time of zero point adjustment and the time of use, the density of the sealing liquid will change with the change in temperature, causing the zero point to shift and cause an error.
本発明はこのような背景の下でなされたもので、その課
題は誤差をなくして正確な計測の行える差圧式計測装置
を提供することにある。The present invention was made against this background, and its object is to provide a differential pressure type measuring device that can eliminate errors and perform accurate measurements.
本発明は前記課題を解決するため、次のような手段をと
った。In order to solve the above problems, the present invention takes the following measures.
本発明の装置は液面計としであるいは密度計として具体
化できるもので、第1の圧力入力部1aと第2の圧力入
力部1bを有しこれら各圧力入力部(1a、1b)に入
力される圧力の差圧を測定する差圧計1を備えている。The device of the present invention can be embodied as a liquid level gauge or a density meter, and has a first pressure input section 1a and a second pressure input section 1b, and inputs are input to each of these pressure input sections (1a, 1b). It is equipped with a differential pressure gauge 1 that measures the differential pressure between the pressures applied.
そして、差圧計1の第1の圧力入力11aが第1の管3
で被測定液を収容する貯溜2に接続されるとともに、差
圧計1の第2の圧力入力部1bが第2の管4で貯溜2に
接続され、かつ、第2の管4と貯溜2との接続点は第1
の管3と貯溜2との接続点よりも高い位置にある。The first pressure input 11a of the differential pressure gauge 1 is connected to the first pipe 3.
The second pressure input part 1b of the differential pressure gauge 1 is connected to the reservoir 2 through the second pipe 4, and the second pipe 4 and the reservoir 2 are connected to each other through the second pipe 4. The connection point is the first
It is located at a higher position than the connection point between the pipe 3 and the reservoir 2.
さらに、第1の管3及び第2の管4の内生なくとも第2
の管4内にシール液が充填され、このシール液の温度を
検知するシール液温度検出手段11が設けられている。Furthermore, the internal structure of the first pipe 3 and the second pipe 4 is at least
The tube 4 is filled with a sealing liquid, and a sealing liquid temperature detection means 11 for detecting the temperature of this sealing liquid is provided.
また、第1の圧力入力部1aに入力される圧力(P++
ρdH)
Pl:貯溜内圧
ρd :被測定液の設計密度
H:第1の圧力入力部1aから被測定液面までの高さ
と第2の圧力入力部1bに入力される圧力(P++ρ、
h)
ρ5:シール液の密度
h :第2の圧力入力部1bから起算したシール液の封
入高さ
とから両者の差圧ΔPを次の(1)式
6式%)
に基づき検出する差圧検出手段13と、差圧計1におい
て予め前記(1)式の右辺に
ρ5hを加えることにより(この時のρ5=ρ50)Δ
P=ρdH・・ (2)
とするゼロ点調整手段30とを備えている。Moreover, the pressure (P++
ρdH) Pl: Reservoir internal pressure ρd: Design density of the liquid to be measured H: Height from the first pressure input part 1a to the liquid level to be measured and the pressure input to the second pressure input part 1b (P++ρ,
h) ρ5: Density of sealing liquid h: Differential pressure detection that detects the differential pressure ΔP between the two based on the sealed height of the sealing liquid calculated from the second pressure input part 1b based on the following equation (1) 6 equation %) By adding ρ5h to the right side of the equation (1) in advance in the means 13 and the differential pressure gauge 1 (ρ5=ρ50 at this time), Δ
P=ρdH (2) A zero point adjustment means 30 is provided.
以上が、)夜面計、密度計に共通の構成であるが、液面
計の場合は、
得られた差圧から被測定液の液面高さHを次の(3)式
%式%(3)
より算出する液面演算手段12と、
ゼロ点調整時の一シール液密度ρ5gと実際の測定時に
おけるシール液密度ρ5aとの差を下記(4)式
%式%(4)
β :シール液の膨張係数/℃
t8:測定時におけるシール液温度
ta :ゼロ点調整時におけるシール液温度から求め
るシール液密度の変動分検出手段15と、1夜面演算手
段12で液面高さを算出する際、ΔP中に包含されるシ
ール液密度の変動分に基づく誤差圧力β(1a−10)
hを打ち消す誤差補正手段31とを備えて差圧式計測装
置とする。The above is a common configuration for night level meters and density meters, but in the case of liquid level meters, the liquid level height H of the measured liquid is calculated from the obtained differential pressure using the following formula (3) % formula % (3) The liquid level calculation means 12 calculates the difference between one seal liquid density ρ5g at the time of zero point adjustment and the seal liquid density ρ5a at the time of actual measurement using the following formula (4) % formula % (4) β: Expansion coefficient of seal liquid/°C t8: Seal liquid temperature at the time of measurement ta: Fluctuation in seal liquid density determined from the seal liquid temperature at the time of zero point adjustment The liquid level height is calculated by the detection means 15 and the surface calculation means 12. When calculating, the error pressure β (1a-10) based on the variation in seal liquid density included in ΔP
A differential pressure type measuring device is provided with an error correction means 31 for canceling h.
また、これとは別に、シール液密度の変動分検出手段1
5と先の誤差補正手段31とを用いず、前記共通事項及
び液面演算手段に加え、液面演算手段12で液面高さを
算出する際、下記の(5)式
β :シール液の膨張係数/℃
te :ゼロ点調整時におけるシール液温度t、:測
定時におけるシール液温度
ρ−:被測定液の設計密度(=固定値)H4:被測定液
の液面高さの測定範囲
でゼロ点移動量ε求め、前記液面演算手段12で演算し
た得た実測値に17(1+ε)を乗じて真値を得るよう
にした誤差補正手段31を備えて差圧式計測装置として
もよい。In addition, apart from this, the seal liquid density variation detection means 1
When calculating the liquid level height using the liquid level calculating means 12 in addition to the above-mentioned common items and the liquid level calculating means without using the error correction means 31 and the error correction means 31 described above, the following equation (5) β: of the sealing liquid Expansion coefficient/°C te: Seal liquid temperature at the time of zero point adjustment, t: Seal liquid temperature at the time of measurement, ρ-: Design density of the measured liquid (=fixed value) H4: Measurement range of the liquid level of the measured liquid The differential pressure measuring device may be provided with an error correction means 31 which calculates the zero point movement amount ε and multiplies the obtained actual value calculated by the liquid level calculation means 12 by 17 (1 + ε) to obtain the true value. .
以上において、hの値を次の(6)式
へPe:ゼロ点調整時の差圧(=測定値)ρs1:基準
温度におけるシール液密度(=固定値)
:シール液の膨張係数/℃(=固定値):ゼロ点調整時
におけるシール液温度
(=測定値)
:任意の基準温度(=固定値)
で演算するh算出手段14を備えるとさらに精度が高ま
る。In the above, the value of h is calculated using the following equation (6). Pe: Differential pressure at zero point adjustment (=measured value) ρs1: Sealing liquid density at reference temperature (=fixed value): Expansion coefficient of sealing liquid/°C ( = fixed value): Seal liquid temperature at the time of zero point adjustment (=measured value): Arbitrary reference temperature (=fixed value) If h calculation means 14 is provided, the accuracy will be further improved.
密度計の場合は、液面計では未知であったHの値をHQ
(第1の圧力入力部1aから第2の管4と貯溜2との接
続点までの高さ)として固定した上で、得られた差圧か
ら被測定液の密度を算出する密度演算手段32を備える
。In the case of a density meter, the value of H, which was unknown with a liquid level meter, can be measured by HQ.
(the height from the first pressure input part 1a to the connection point between the second pipe 4 and the reservoir 2), and then the density calculation means 32 calculates the density of the liquid to be measured from the obtained differential pressure. Equipped with.
すなわち、前記共通事項において、第2の管4と貯溜2
との接続点より液面が高くなるように被測定ン夜を貯溜
2に入れた状態とすることでHがHQとなり、第1の圧
力入力部1aに入力される圧力が(P’++ρL+ρ8
9)となり、Pl:貯溜内圧
ρ :被測定液の密度(未知)
L :第2の管4と貯溜2との接続点から被測定液面ま
での高さ
HQ:第1の圧力入力部1aから第2の管4と貯溜2と
の接続点までの高さ
と第2の圧力入力部1bに入力される圧力が(P++ρ
L+ρ、h)となるので
ρs:シール液の密度
h :第2の圧力入力部1bから起算したシーツ1夜の
封入高さ(ここではh=HQ)差圧検出手段13では両
者の差圧ΔPを次の(1)′式
%式%)
に基づき検出する。That is, in the common matter mentioned above, the second pipe 4 and the reservoir 2
By placing the liquid to be measured in the reservoir 2 so that the liquid level is higher than the connection point with
9), Pl: Reservoir internal pressure ρ: Density of the liquid to be measured (unknown) L: Height from the connection point between the second pipe 4 and the reservoir 2 to the liquid level to be measured HQ: First pressure input section 1a to the connection point between the second pipe 4 and the reservoir 2 and the pressure input to the second pressure input part 1b are (P++ρ
L + ρ, h), so ρs: Density of sealing liquid h: Sealing height of one sheet per night calculated from the second pressure input section 1b (Here, h = HQ) The differential pressure detection means 13 calculates the differential pressure ΔP between the two. is detected based on the following (1)' formula (%).
また、ゼロ点調整手段30も、前記HがHQに変わり、
差圧計1において予め前記(1)′式の右辺に
ρ、HQを加えることにより(この時のρ5=ρ50)
八P=pHQ ・・(2)′とす
る。Also, in the zero point adjustment means 30, the H is changed to HQ,
In differential pressure gauge 1, by adding ρ and HQ to the right side of equation (1)′ in advance (ρ5 = ρ50 at this time)
8P=pHQ...(2)'.
密度計では、さらに得られた差圧から被測定液の密度ρ
を次の(8)式
%式%(8)
より算出する密度演算手段32と、
ゼロ点調整時のシール液密度ρ5aと実際の測定時にお
けるシール液密度ρsaとの差を下記(4)D sa
D 5G =β (ta−tc+) ・ ◆
(4)β :シール液の膨張係数/℃
t、:測定時におけるシール液温度
tlI:ゼロ点調整時に$けるシール液温度から求める
シール液密度の変動分検出手段15と、密度演算手段3
2で液密度を算出する際、ΔP中に包含されるシール液
密度の変動分に基づく誤差圧力β(ta−t9)hを打
ち消す誤差補正手段31とを備えて差圧式計測装置とす
る。In addition, the density meter calculates the density ρ of the liquid to be measured from the obtained differential pressure.
The density calculation means 32 calculates the difference between the seal liquid density ρ5a at the time of zero point adjustment and the seal liquid density ρsa at the time of actual measurement using the following (4) D. sa
D 5G = β (ta-tc+) ・ ◆
(4) β: Expansion coefficient of sealing liquid/℃ t,: Seal liquid temperature at the time of measurement tlI: Fluctuation detection means 15 of seal liquid density determined from seal liquid temperature at zero point adjustment, and density calculation means 3
When calculating the liquid density in step 2, the differential pressure measuring device is provided with an error correction means 31 for canceling the error pressure β(ta-t9)h based on the variation in sealing liquid density included in ΔP.
また、これとは別に、シール液密度の変動分検出手段1
5や先の誤差補正手段31を用いずに、この密度演算手
段32で液密度を算出する際、下記の(9)式
%式%(9)
β :シール液の膨張係数/℃
tl:測定時におけるシール液温度
tθ:ゼロ点調整時におけるシール液温度ρ、:被測定
液の密度測定範囲の最大値h :第2の圧力入力部1b
から起算したシール液の封入高さ
HQ:第1の圧力入力部1aから第2の管4と貯溜2と
の接続点までの高さ
でゼロ点移動量ε求め、前記密度演算手段32で演算し
た得た実測値ζこ1/(1+ε)を乗じて真値を得るよ
うにした誤差補正手段31を備えて差圧式計測装置とし
てもよい。In addition, apart from this, the seal liquid density variation detection means 1
When calculating the liquid density with this density calculating means 32 without using the error correction means 31 described in 5 and above, the following formula (9) % formula % (9) β: Expansion coefficient of sealing liquid/°C tl: Measurement Seal liquid temperature tθ at time: Seal liquid temperature ρ at zero point adjustment: Maximum value h of the density measurement range of the liquid to be measured: Second pressure input section 1b
Sealing liquid height HQ calculated from: The zero point movement amount ε is determined from the height from the first pressure input part 1a to the connection point between the second pipe 4 and the reservoir 2, and the density calculation means 32 calculates it. The differential pressure measuring device may be provided with an error correction means 31 which multiplies the obtained actual measurement value ζ by 1/(1+ε) to obtain the true value.
本発明では、液面計の場合、測定可能な液面高さの最大
値をH,、lとして、貯溜2にシール液供給手段でシー
ル液の供給を開始する。In the present invention, in the case of a liquid level gauge, the maximum measurable liquid level height is set to H, 1, and the sealing liquid supply means starts supplying the sealing liquid to the reservoir 2.
そして、計器をゼロ点調整した後、差圧検出手段13で
第1圧力入力部に加わる圧力と第2圧力入力部に加わる
圧力との差を検出する。After zeroing the meter, the differential pressure detection means 13 detects the difference between the pressure applied to the first pressure input part and the pressure applied to the second pressure input part.
その間、目標の液面高さHIllを得るのに必要なhの
値を算出しておく。但し、hの値を設計値(固定値)と
して(6)式以外で与えることもてきる。Meanwhile, the value of h required to obtain the target liquid level height HIll is calculated. However, the value of h can be given as a design value (fixed value) using a method other than equation (6).
また、前記差圧から実際の液面高さHを算出する。Furthermore, the actual liquid level height H is calculated from the differential pressure.
ゼロ点調整時と実際の測定時で環境温度が変わりゼロ点
調整時のシール液密度ρ53と実際の測定時におけるシ
ール液密度ρs8とに差が生じると得られた測定値に誤
差が生ずるので、シール液密度の差を(4)式から求め
、その変動分に基づく誤差圧力β(ta−tta) h
を打ち消して真値を得る。If the environmental temperature changes between zero point adjustment and actual measurement, and there is a difference between the seal liquid density ρ53 during zero point adjustment and the seal liquid density ρs8 during actual measurement, an error will occur in the obtained measured value. Calculate the difference in seal liquid density from equation (4), and calculate the error pressure β (ta-tta) h based on the variation.
Cancel and get the true value.
これとは別に、液面高さを算出する際、(5)式でゼロ
点移動量ε求め、前記液面演算手段12で演算した得た
実測値に17(1+ε)を乗じて真値を得るようにして
も誤差を補正できる。Separately, when calculating the liquid level height, the zero point movement amount ε is calculated using equation (5), and the actual value calculated by the liquid level calculation means 12 is multiplied by 17 (1 + ε) to obtain the true value. The error can be corrected even if the
密度計の場合も得られた密度の実測値に同様にして誤差
補正する。なお、密度計として使用する場合、第2の管
4と貯溜2との接続点より液面が高くなるように被測定
液を貯溜2に入れるため、h=HQとなり、各式で直接
りの値を使用する必要がないため、hの算出を前記のよ
うにする必要はない。In the case of a densitometer, the error is corrected in the same way for the actual density value obtained. When used as a density meter, the liquid to be measured is put into the reservoir 2 so that the liquid level is higher than the connection point between the second pipe 4 and the reservoir 2, so h=HQ, and each equation directly calculates the Since there is no need to use a value, there is no need to calculate h as described above.
以下、本発明の実施例を図面に基づいて説明する。 Embodiments of the present invention will be described below based on the drawings.
〈実施例1〉
本実施例の装置は液面計であり、第2図に示したように
、第1の圧力入力部1aと第2の圧力入力部1bを有し
これら各圧力入力部(la、 lb)に入力される圧
力の差圧を測定する差圧計1が備えられている。また、
被測定液を収容する貯溜2の上部に被測定液を供給する
ための被測定液供給管2aが接続され、この被測定液供
給管2aにバルブ24が設けられ、貯溜2へ被測定液の
供給をバルブ24の開閉で開始・停止できるようになっ
ている。<Example 1> The device of this example is a liquid level gauge, and as shown in FIG. 2, it has a first pressure input section 1a and a second pressure input section 1b. A differential pressure gauge 1 is provided to measure the differential pressure between the pressures input to the terminals (la, lb). Also,
A liquid to be measured supply pipe 2a for supplying the liquid to be measured is connected to the upper part of the reservoir 2 that accommodates the liquid to be measured, and a valve 24 is provided to this liquid to be measured pipe 2a to supply the liquid to be measured to the reservoir 2. Supply can be started and stopped by opening and closing the valve 24.
また、差圧計1の第1の圧力入力部1aが第1の管3で
貯溜2に接続されるとともに、差圧計1の第2の圧力入
力部1bが第2の管4で貯溜2に接続され、かつ、第2
の管4と貯溜2との接続点は第1の管3と貯溜2との接
続点よりも高い位置にある。Further, the first pressure input part 1a of the differential pressure gauge 1 is connected to the reservoir 2 through the first pipe 3, and the second pressure input part 1b of the differential pressure gauge 1 is connected to the reservoir 2 through the second pipe 4. and the second
The connection point between the first tube 4 and the reservoir 2 is located at a higher position than the connection point between the first tube 3 and the reservoir 2.
さらに、第1及び第2の管4内にシール液が充填され、
このシール液の温度を検知するシール液温度検出手段1
1が設けられている。Furthermore, the first and second tubes 4 are filled with sealing liquid,
Seal liquid temperature detection means 1 for detecting the temperature of this seal liquid
1 is provided.
また、この第1の圧力入力部1aに入力される圧力と第
2の圧力入力部1bに入力される圧力とから両者の差圧
を検出する差圧検出手段13を有している。Further, it has differential pressure detection means 13 that detects the differential pressure between the pressure input to the first pressure input section 1a and the pressure input to the second pressure input section 1b.
ここで第1の圧力入力部1aに入力される圧力は式
%式%
:
ρd:被測定液の設計密度
H:第1の圧力入力部1aから被測定液面までの高さ(
未知)
第2の圧力入力部1bに入力される圧
で表され、
力は式
%式%
ρs:シール液の密度
h :第2の圧力入力部1bから起算したシール液の封
入高さ
で表されるので、その差圧△Pは、
ΔP=(Pt+ρdH) (P++o5h)=ρd
H−ρ5h ・・(1)である。Here, the pressure input to the first pressure input section 1a is calculated using the following formula: ρd: Design density of the liquid to be measured H: Height from the first pressure input section 1a to the surface of the liquid to be measured (
unknown) The force is expressed by the pressure input to the second pressure input part 1b, and the force is expressed by the formula %. Therefore, the differential pressure ΔP is as follows: ΔP=(Pt+ρdH) (P++o5h)=ρd
H-ρ5h...(1).
そこで、得られた差圧から被測定液の液面高さを算出す
る液面演算手段12で液面を算出するのであるが、算出
にあたってはゼロ点調整手段3゜で、差圧計1において
予め前記(1)式の右辺にρ5hを加えることにより(
この時のρ5=ρ5illとする)
ΔP=ρdH・・ (2)
とする。よって、液面演算手段12では、得られた差圧
から被測定液の液面高さHを次の(3)弐H=ΔP/ρ
d ◆・(3)より算出すればよいこ
ととなる。Therefore, the liquid level is calculated by the liquid level calculation means 12 which calculates the liquid level height of the liquid to be measured from the obtained differential pressure. By adding ρ5h to the right side of equation (1) above, (
At this time, ρ5 = ρ5ill) ΔP = ρdH (2). Therefore, the liquid level calculation means 12 calculates the liquid level H of the measured liquid from the obtained differential pressure by the following (3) 2H=ΔP/ρ
d ◆・It can be calculated from (3).
このようにして液面高さが得られるが、ゼロ点調整時と
測定時どの間に温度変化が生じ、シール液密度が変化す
ると(1)式における(−〇、h)が確実にキャンセル
されたこととならないため、実測値に誤差が含まれたこ
ととなる。The liquid level height can be obtained in this way, but if a temperature change occurs between zero point adjustment and measurement, and the sealing liquid density changes, (-〇, h) in equation (1) will definitely be canceled. This means that the actual measured value contains an error.
そこで、シール液密度の変動分検出手段15を設け、ゼ
ロ点調整時のシール液密度ρ5Qと実際の測定時におけ
るシール液密度ρ5aとの差を下記(4)式
%式%(4)
β :シール液の膨張係数/℃
t、:測定時におけるシール液温度
t、:ゼロ点調整時におけるシール液温度から求める。Therefore, a means 15 for detecting fluctuations in seal liquid density is provided, and the difference between the seal liquid density ρ5Q at the time of zero point adjustment and the seal liquid density ρ5a at the time of actual measurement is calculated using the following formula (4) % formula % (4) β: Expansion coefficient of sealing liquid/°C t: Seal liquid temperature at the time of measurement t: Determined from the seal liquid temperature at the time of zero point adjustment.
ゼロ調整時に補正するために(1)式の右辺に加算した
圧力ρs[111に対し、測定時のシール液実圧力(ρ
58+β(t、−to))hとなり、両者の差β(t−
t9)hが誤差圧力となる。よって、この値を液面演算
手段12で液面高さを算出する際、ΔP中から誤差補正
手段31で打ち消す。For the pressure ρs [111 added to the right side of equation (1) to correct during zero adjustment, the actual sealing liquid pressure at the time of measurement (ρ
58+β(t,-to))h, and the difference between the two is β(t-
t9) h becomes the error pressure. Therefore, when calculating the liquid level height by the liquid level calculation means 12, this value is canceled by the error correction means 31 from ΔP.
以上により、論理的に誤差を解消できるが、より具体的
には以下の手段によるのがよい。As described above, the error can be solved logically, but more specifically, the following method is preferable.
まず、シール液密度の温度変化と計器誤差(ゼロ点移動
量ε)の関係は下記の(5)式β :シール液の膨張
係数/℃(=固定(a)t[I:ゼロ点調整時における
シール液温度ta:測定時におけるシール液温度
ρd :被測定液の設計密度(=固定値)H7:被測
定液の液面高さの測定範囲
(=固定値)
tl:シール液封入高さ
で表せるので、誤差補正手段31としては、この式から
ゼロ点移動量ε求め、前記液面演算手段12で演算した
得た実測値に1/(1+ε)を乗じて真値を得るように
するとよい。First, the relationship between the temperature change in sealing liquid density and the instrument error (zero point movement amount ε) is expressed by the following equation (5) β: Expansion coefficient of sealing liquid / °C (= fixed (a) t[I: at zero point adjustment Seal liquid temperature ta: Seal liquid temperature at the time of measurement ρd: Design density of the measured liquid (=fixed value) H7: Measurement range of liquid level height of the measured liquid (=fixed value) tl: Seal liquid filled height Since it can be expressed as good.
ところで、h(シール液封入高さ)は固定値であるが、
設計段階・の設定値と配管施工後の実際の1直とでは差
があるのが通常である。そして、配管施工後のh実測作
業も難しいことから、hの値をゼロ点調整時に演算する
ことを考えた。By the way, h (sealing liquid filling height) is a fixed value,
There is usually a difference between the set values at the design stage and the actual first shift after piping construction. Since it is difficult to actually measure h after piping construction, we considered calculating the value of h during zero point adjustment.
ゼロ点調整時差圧計にはΔP9=−ρ5θhの圧力が加
わる。(−)符号は低圧側にρ5tahの圧力が加わっ
ていることを意味する。よって、hの1直を
h=−八P9/ρ53
で演算できる。A pressure of ΔP9=−ρ5θh is applied to the differential pressure gauge during zero point adjustment. The (-) sign means that a pressure of ρ5tah is applied to the low pressure side. Therefore, one shift of h can be calculated as h=-8P9/ρ53.
ここで、ゼロ点調整時のシール液密度ρ5gはその時の
温度上〇で決まるが、一定の温度で実施することはでき
ない。そこで、任意の基準温度をtl、基準温度におけ
るシール液密度をρ51とするとρ51a=ρ51+β
(tc+−t+)となるので、次の(6)式
ΔP&l:ゼロ点調整時の差圧(=測定値)ρ51:基
準温度におけるシール液密度(=固定値)
:シール液の膨張係数/℃(=固定値):ゼロ点調整時
におけるシール液温度
(=測定値)
:任意の基準温度(=固定値)
でhを演算する。Here, the seal liquid density ρ5g at the time of zero point adjustment is determined by the temperature at that time, but it cannot be carried out at a constant temperature. Therefore, if an arbitrary reference temperature is tl and the sealing liquid density at the reference temperature is ρ51, then ρ51a=ρ51+β
(tc+-t+), so the following equation (6) ΔP&l: Differential pressure at zero point adjustment (=measured value) ρ51: Sealing liquid density at reference temperature (=fixed value): Expansion coefficient of sealing liquid/°C (=fixed value): Seal liquid temperature during zero point adjustment (=measured value): Calculate h using any reference temperature (=fixed value).
そこで、この(6)式を前記(5)式に代入すると、 ・ ・ (7) となる。Therefore, by substituting this equation (6) into the above equation (5), we get ・ ・ (7) becomes.
ここで、β、ρd5 ρ51、tl、H,は固定値であ
り、tra1△P9はゼロ点調整時にメモリーに保存し
ておいたデータを使用する。Here, β, ρd5 ρ51, tl, and H are fixed values, and tra1ΔP9 uses data stored in the memory at the time of zero point adjustment.
よって、taを測定することで、εを自動補正できる。Therefore, by measuring ta, ε can be automatically corrected.
以上は、マイクロコンピュータに絹み込まれたプログラ
ムによ−り第2図のフローチャー1・図のように実行さ
れる。The above steps are executed as shown in flowchart 1 of FIG. 2 by a program installed in the microcomputer.
まず、ステップ1で、Hm (?(7面高さの最大測定
範囲)、ρd(被測定液の設計密度)、β(シール液の
膨張係数/℃)、1+ (基準温度)、ρ5゜(基準
温度におけるシール液密度)を入力する。First, in step 1, Hm (? (maximum measurement range of seven surface heights), ρd (design density of the liquid to be measured), β (sealing liquid expansion coefficient/°C), 1+ (reference temperature), ρ5゜( Enter the seal liquid density at the reference temperature.
次にステップ2で計器単体ゼロ調フラグF1を確認する
(F 1 = 1で計器単体ゼロ調実施)。ここでNO
の場合ゼロ調整を行わずに実測に入ることを意味し、そ
のままステップ15へと移行する。Next, in step 2, the instrument unit zero adjustment flag F1 is checked (instrument unit zero adjustment is performed when F 1 = 1). NO here
In the case of , it means that actual measurement is started without performing zero adjustment, and the process directly proceeds to step 15.
Yesの場合は、ステップ3で計器単体ゼロ調が完了し
たかを確認する。NOの場合ステ・ンブ4の計器単体ゼ
ロ調実施に移行してステ・ンブ3に戻り、Yesの場合
にはステップ5で計器単体ゼロ調フラグF1=0が立て
られる。In the case of Yes, it is confirmed in step 3 whether zero adjustment of the instrument itself is completed. If NO, the process moves to step 4 to carry out zero adjustment of the individual instrument, and returns to step 3; if YES, the individual instrument zero adjustment flag F1=0 is set in step 5.
次にステップ6でシール液を使用しゼロ調整実施の準備
が順次なされ、ステップ7でゼロ調整時の温度tc+、
差圧ΔP9が測定される。ここで、測定された温度tl
I、差圧△P9が妥当な値か否かを判断しくステップ8
)、妥当でない場合はステップ3へと戻る。妥当な場合
にはシール液を使用したゼロ調整時演算実行フラグF2
=1が立てられ(ステップ9)、t9、△P9が記憶さ
れ、hが演算されその値が記憶される(ステップ10)
。Next, in step 6, preparations for zero adjustment are made sequentially using sealing liquid, and in step 7, the temperature at the time of zero adjustment, tc+,
A differential pressure ΔP9 is measured. Here, the measured temperature tl
Step 8: Determine whether I and differential pressure △P9 are appropriate values.
), if it is not valid, return to step 3. Calculation execution flag F2 during zero adjustment using seal liquid if appropriate
=1 is set (step 9), t9 and ΔP9 are stored, h is calculated and its value is stored (step 10)
.
次に、hの値が妥当か否かを判断しくステップ11)、
妥当でない場合はステップ3に戻り、妥当である場合は
シール液が入った状態でのゼロ点調整を行う(ステップ
12)。次に、実際の測定時へのラインアップを行い(
ステップ13)、h演算実行フラグF2を0にする(ス
テップ14)。Next, it is determined whether the value of h is appropriate or not (Step 11),
If it is not appropriate, return to step 3, and if it is appropriate, zero point adjustment is performed with sealing liquid in it (step 12). Next, perform the lineup for the actual measurement (
Step 13), and set the h operation execution flag F2 to 0 (Step 14).
ステップ15では運転中における実測が開始されてΔP
が測定される。その際には、シール液温度t8が測定さ
れ、εが(7)式により演算される(ステップ16)。In step 15, actual measurement during operation is started and ΔP
is measured. At that time, the sealing liquid temperature t8 is measured, and ε is calculated using equation (7) (step 16).
そして、そのデータを基に真のHを演算する(ステップ
17)。Then, the true H is calculated based on the data (step 17).
〈実施例2〉 実施例2は密度計の場合である。<Example 2> Example 2 is a case of a density meter.
この場合、第3図のように、実施例1における液面演算
手段12に代えて、得られた差圧から被測定液の密度を
算出する密度演算手段32を有している。In this case, as shown in FIG. 3, in place of the liquid level calculation means 12 in the first embodiment, there is provided a density calculation means 32 for calculating the density of the liquid to be measured from the obtained differential pressure.
そして、液面計の場合と異なり第2の管4と貯溜2との
接続点より液面が高くなるように被測定液が貯溜2に入
れられる。このためh=H1l!となり、よって、第1
の圧力入力部1aに入力される圧力は
(P++ρL+pH1ll)
Pl :貯溜内圧
ρ :被測定液の密度(未知)
L :第2の管4と貯溜2との接続点から被測定液面ま
での高さ
HQ :第1の圧力入力部1aから第2の管4と貯溜2
との接続点までの高さ
となり、第2の圧力入力部1bに入力される圧力は(P
++ρL+ρ、h)
ρ5:シール液の密度
h :第2の圧力入力部1bから起算したシール液の封
入高さ(ここではh=HQ)となるので、両者の差圧Δ
Pを次の(1)”式0式%)
に基づき検出する。Then, unlike in the case of a liquid level gauge, the liquid to be measured is put into the reservoir 2 so that the liquid level is higher than the connection point between the second pipe 4 and the reservoir 2. Therefore h=H1l! Therefore, the first
The pressure input to the pressure input section 1a is (P++ρL+pH1ll) Pl: Reservoir internal pressure ρ: Density of the liquid to be measured (unknown) L: Height from the connection point between the second pipe 4 and the reservoir 2 to the level of the liquid to be measured HQ: From the first pressure input part 1a to the second pipe 4 and the reservoir 2
and the pressure input to the second pressure input section 1b is (P
++ρL+ρ, h) ρ5: Density of the sealing liquid h: The sealing liquid height calculated from the second pressure input part 1b (here, h=HQ), so the differential pressure Δ between the two
P is detected based on the following (1) "Formula 0 Formula %)".
またゼロ点調整においても、差圧計1において予め前記
(1)式の右辺にρ5HQ を加えることにより(この
時のOs”ρ58)
ΔP=pHQ ・・ (2)′
とする。Also, in the zero point adjustment, by adding ρ5HQ to the right side of the equation (1) in advance in the differential pressure gauge 1 (Os"ρ58 at this time), ΔP=pHQ... (2)'
shall be.
そして密度演算手段32では、得られた差圧から被測定
液の密度ρを次の(8)式
0式%(8)
より算出する。Then, the density calculating means 32 calculates the density ρ of the liquid to be measured from the obtained differential pressure using the following equation (8).
ゼロ点調整時のシール液密度05Gと実際の測定時にお
けるシール液密度ρ5aとの差をから生ずる誤差、及び
、その補正は、先の実施例の場合と同様に考えてよいが
、密度計の場合、H,というデータはHQに置き変わり
、密度の最大値ρdmが導入されるので、前記(5)式
は次の(9)式に変更される。The error caused by the difference between the seal liquid density 05G at the time of zero point adjustment and the seal liquid density ρ5a at the time of actual measurement and its correction can be considered in the same way as in the previous example, but the density meter In this case, the data H is replaced with HQ, and the maximum density value ρdm is introduced, so the equation (5) is changed to the following equation (9).
β :シール液の膨張係数7℃
t8:測定時におけるシール液温度
t9:ゼロ点調整時におけるシール液温度ρ、:被測定
液の密度測定範囲の最大値h :第2の圧力入力部1b
から起算したシール液の封入高さ
HQ:第1の圧力入力部1aから第2の管4と貯溜2と
の接続点までの高さ
ここで、密度計の場合、h=HQであるため(9)式は
、
ブロック図、第2図はそのフローチャート図、第3図は
本発明に係る液面計の実施例を示したブロック図、第4
図は従来例を示した図である。β: Expansion coefficient of seal liquid 7°C t8: Seal liquid temperature at the time of measurement t9: Seal liquid temperature at the time of zero point adjustment ρ,: Maximum value of the density measurement range of the liquid to be measured h: Second pressure input section 1b
Sealing liquid height HQ calculated from: Height from the first pressure input part 1a to the connection point between the second pipe 4 and the reservoir 2Here, in the case of a density meter, since h=HQ, ( 9) is a block diagram, FIG. 2 is a flow chart thereof, FIG. 3 is a block diagram showing an embodiment of the liquid level gauge according to the present invention, and FIG.
The figure shows a conventional example.
1・・差圧計、1a・・第1の圧力入力部、1b・・第
2の圧力入力部、2・・貯溜、3・・第1の管、4◆◆
第2の管、11φ・シール液温度検出手段、12・・液
面演算手段、13・・差圧検出手段、14・・h算出手
段、30・・ゼロ点調整手段、31・・誤差補正手段、
32・・密度演算手段。1...Differential pressure gauge, 1a...First pressure input part, 1b...Second pressure input part, 2...Storage, 3...First pipe, 4◆◆
Second pipe, 11φ・Seal liquid temperature detection means, 12..Liquid level calculation means, 13..Differential pressure detection means, 14..h calculation means, 30..Zero point adjustment means, 31..Error correction means ,
32...Density calculation means.
となる。この式でゼロ点移動量ε求め、前記密度演算手
段32で演算した得た実測値に1/(1+ε)を乗じて
真値を得る。becomes. The zero point movement amount ε is determined using this formula, and the actual value calculated by the density calculation means 32 is multiplied by 1/(1+ε) to obtain the true value.
本発明では、温度変化に伴う測定値の誤差をなくし正確
な計測値を得ることができる。According to the present invention, it is possible to eliminate errors in measurement values due to temperature changes and obtain accurate measurement values.
第1図は本発明に係る液面計の実施例を示した特許出願
人 三井石油化学工業株式会社第2図
(b)
第3図
第4図Figure 1 shows an embodiment of the liquid level gauge according to the present invention, patent applicant Mitsui Petrochemical Industries, Ltd. Figure 2 (b) Figure 3 Figure 4
Claims (1)
有しこれら各圧力入力部(1a、1b)に入力される圧
力の差圧を測定する差圧計1を備え、この差圧計1の第
1の圧力入力部1aが第1の管3で測定液を収容する貯
漕2に接続されるとともに、差圧計1の第2の圧力入力
部1bが第2の管4で貯漕2に接続され、かつ、第2の
管4と貯漕2との接続点は第1の管3と貯漕2との接続
点よりも高い位置にあり、さらに、第1の管3及び第2
の管4の内少なくとも第2の管4内にシール液が充填さ
れ、このシール液の温度を検知するシール液温度検出手
段11が設けられ、さらに、この第1の圧力入力部1a
に入力される圧力 (P_1+ρ_dH) P_1:貯漕内圧 ρ_d:被測定液の設計密度 H:第1の圧力入力部1aから被測定液面 までの高さ(未知) と第2の圧力入力部1bに入力される圧力 (P_1+ρ_sh) ρ_s:シール液の密度 h:第2の圧力入力部1bから起算したシ ール液の封入高さ とから両者の差圧ΔPを次の(1)式 △P=(P_1+ρ_dH)−(P_1+ρ_sh)=
ρ_dH−ρ_sh・・(1) に基づき検出する差圧検出手段13と、 差圧計1において予め前記(1)式の右辺にρ_shを
加えることにより(この時のρ_s=ρ_s_0)△P
=ρ_dH・・(2) とするゼロ点調整手段30と、 得られた差圧から被測定液の液面高さHを次の(3)式 H=ΔP/ρ_d・・(3) より算出する液面演算手段12と、 ゼロ点調整時のシール液密度ρ_s_0と実際の測定時
におけるシール液密度ρ_s_aとの差を下記(4)式 ρ_s_a−ρ_s_0=β(t_a−t_0)・・(
4)β:シール液の膨張係数/℃ t_a:測定時におけるシール液温度 t_0:ゼロ点調整時におけるシール液温度から求める
シール液密度の変動分検出手段15と、液面演算手段1
2で液面高さを算出する際、△P中に包含されるシール
液密度の変動分に基づく誤差圧力β(t_a−t_0)
hを打ち消す誤差補正手段31とを備えたことを特徴と
する差圧式計測装置。 【2】第1の圧力入力部1aと第2の圧力入力部1bを
有しこれら各圧力入力部(1a、1b)に入力される圧
力の差圧を測定する差圧計1を備え、この差圧計1の第
1の圧力入力部1aが第1の管3で測定液を収容する貯
漕2に接続されるとともに、差圧計1の第2の圧力入力
部1bが第2の管4で貯漕2に接続され、かつ、第2の
管4と貯漕2との接続点は第1の管3と貯漕2との接続
点よりも高い位置にあり、さらに、第1の管3及び第2
の管4の内少なくとも第2の管4内にシール液が充填さ
れ、このシール液の温度を検知するシール液温度検出手
段11が設けられ、さらに、この第1の圧力入力部1a
に入力される圧力(P_1+ρ_dH) P_1:貯漕内圧 ρ_d:被測定液の設計密度 H:第1の圧力入力部1aから被測定液 面までの高さ(未知) と第2の圧力入力部1bに入力される圧力 (P_1+ρ_sh) ρ_s:シール液の密度 h:第2の圧力入力部1bから起算した シール液の封入高さ とから両者の差圧ΔPを次の(1)式 ΔP=(P_1+ρ_dH)−(P_1+ρ_sh)=
ρ_dH−ρ_sh・・(1) に基づき検出する差圧検出手段13と、 差圧計1において予め前記(1)式の右辺にρ_s_h
を加えることにより(この時のρ_s=ρ_s_0)Δ
P=ρ_dH・・(2) とするゼロ点調整手段30と、 得られた差圧から被測定液の液面高さHを次の(3)式 H=ΔP/ρ_d・・(3) より算出する液面演算手段12と、 この液面演算手段12で液面高さを算出する際、下記の
(5)式 ε=[−β(t_a−t_0)h]/(ρ_dH_m)
・・(5) β:シール液の膨張係数/℃ t_0:ゼロ点調整時におけるシール液温度t_a:測
定時におけるシール液温度 ρ_d:被測定液の設計密度(=固定値) H_m:被測定液の液面高さの測定範囲 でゼロ点移動量ε求め、前記液面演算手段12で演算し
た得た実測値に1/(1+ε)を乗じて真値を得るよう
にした誤差補正手段31とを備えた差圧式計測装置。 【3】hの値を次の(6)式 h=(−ΔP_0)/[ρ_s_1+β(t_0−t_
1)]・・(6)ΔP_0:ゼロ点調整時の差圧(=測
定値)ρ_s_1:任意の基準温度におけるシール液密
度 (=固定値) β:シール液の膨張係数/℃(=固定値) t_0:ゼロ点調整時におけるシール液温度(=測定値
) t_1:任意の基準温度(=固定値) で演算するh算出手段14を備えた請求の範囲第1項ま
たは第2項記載の差圧式計測装置。 【4】第1の圧力入力部1aと第2の圧力入力部1bを
有しこれら各圧力入力部(1a、1b)に入力される圧
力の差圧を測定する差圧計1を備え、この差圧計1の第
1の圧力入力部1aが第1の管3で測定液を収容する貯
漕2に接続されるとともに、差圧計1の第2の圧力入力
部1bが第2の管4で貯漕2に接続され、かつ、第2の
管4と貯漕2との接続点は第1の管3と貯漕2との接続
点よりも高い位置にあり、さらに、第1の管3及び第2
の管4の内少なくとも第2の管4内にシール液が充填さ
れ、このシール液の温度を検知するシール液温度検出手
段11が設けられ、さらに、第2の管4と貯漕2との接
続点より液面が高くなるように被測定液を貯漕2に入れ
た状態で、第1の圧力入力部1aに入力される圧力 (P_1+ρ_L+ρHl) P_1:貯漕内圧 ρ:被測定液の密度(未知) L:第2の管4と貯漕2との接続点から被 測定液面までの高さ Hl:第1の圧力入力部1aから第2の管4と貯漕2と
の接続点までの高さ と第2の圧力入力部1bに入力される圧力 (P_1+ρL+ρ_sh) ρ_s:シール液の密度 h:第2の圧力入力部1bから起算したシ ール液の封入高さ(ここではh=Hl) とから両者の差圧△Pを次の(1)′式 △P=(P_1+ρL+ρHl) −(P_1+ρL+ρ_sh) =ρHl−ρ_sh =ρHl−ρ_sHl・・(1)′ に基づき検出する差圧検出手段13と、 差圧計1において予め前記(1)′式の右辺にρ_sH
lを加えることにより(この時のρ_s=ρ_s_0)
ΔP=ρHl・・(2)′ とするゼロ点調整手段30と、 得られた差圧から被測定液の密度ρを次の(8)式 ρ=ΔP/Hl・・(8) より算出する密度演算手段32と、 ゼロ点調整時のシール液密度ρ_s_0と実際の測定時
におけるシール液密度ρ_s_aとの差を下記(4)式 ρ_s_a−ρ_s_0=β(ta−t_0)・・(4
)β:シール液の膨張係数/℃ t_a:測定時におけるシール液温度 t_0:ゼロ点調整時におけるシール液温度から求める
シール液密度の変動分検出手段15と、密度演算手段3
2で液密度を算出する際、ΔP中に包含されるシール液
密度の変動分に基づく誤差圧力β(t_a−t_0)h
を打ち消す誤差補正手段31とを備えたことを特徴とす
る差圧式計測装置。 【5】第1の圧力入力部1aと第2の圧力入力部1bを
有しこれら各圧力入力部(1a、1b)に入力される圧
力の差圧を測定する差圧計1を備え、この差圧計1の第
1の圧力入力部1aが第1の管3で測定液を収容する貯
漕2に接続されるとともに、差圧計1の第2の圧力入力
部1bが第2の管4で貯漕2に接続され、かつ、第2の
管4と貯漕2との接続点は第1の管3と貯漕2との接続
点よりも高い位置にあり、さらに、第1の管3及び第2
の管4の内少なくとも第2の管4内にシール液が充填さ
れ、このシール液の温度を検知するシール液温度検出手
段11が設けられ、さらに、第2の管4と貯漕2との接
続点より液面が高くなるように被測定液を貯漕2に入れ
た状態で、第1の圧力入力部1aに入力される圧力 (P_1+ρL+pHl) P_1:貯漕内圧 ρ:被測定液の密度(未知) L:第2の管4と貯漕2との接続点から被 測定液面までの高さ Hl:第1の圧力入力部1aから第2の管4と貯漕2と
の接続点までの高さ と第2の圧力入力部1bに入力される圧力 (P_1+ρL+p_sh) ρ_s:シール液の密度 h:第2の圧力入力部1bから起算したシ ール液の封入高さ(ここではh=Hl) とから両者の差圧ΔPを次の(1)′式 ΔP=(P_1+ρL+ρHl) −(P_1+ρL+ρ_sh) =ρHl−ρ_sh =ρHl−ρ_sHl・・(1)′ に基づき検出する差圧検出手段13と、 差圧計1において予め前記(1)′式の右辺にρ_sH
lを加えることにより(この時のρ_s=ρ_s0)△
P=ρHl・・(2)′ とするゼロ点調整手段30と、 得られた差圧から被測定液の密度ρを次の(8)式 ρ=ΔP/Hl・・(8) より算出する密度演算手段32と、 この密度演算手段32で液密度を算出する際、下記の(
9)式 ε=[−β(t_a−t_0)h]/ρ_mHl・・(
9)β:シール液の膨張係数/℃ t_a:測定時におけるシール液温度 t_0:ゼロ点調整時におけるシール液温度ρ_m:被
測定液の密度測定範囲の最大値 h:第2の圧力入力部1bから起算した シール液の封入高さ Hl:第1の圧力入力部1aから第2の管 4と貯溜2との接続点までの高さ でゼロ点移動量ε求め、前記密度演算手段32で演算し
た得た実測値に1/(1+ε)を乗じて真値を得るよう
にした誤差補正手段31とを備えたことを特徴とする差
圧式計測装置。[Scope of Claims] [1] A differential pressure gauge that has a first pressure input section 1a and a second pressure input section 1b and measures the differential pressure between the pressures input to each of these pressure input sections (1a, 1b). 1, the first pressure input part 1a of the differential pressure gauge 1 is connected to the storage tank 2 containing the measurement liquid through the first pipe 3, and the second pressure input part 1b of the differential pressure gauge 1 is connected to the storage tank 2 containing the measuring liquid. The second pipe 4 is connected to the storage tank 2, and the connection point between the second pipe 4 and the storage tank 2 is located at a higher position than the connection point between the first pipe 3 and the storage tank 2, and further, first tube 3 and second tube
At least the second tube 4 of the tubes 4 is filled with a sealing liquid, and a sealing liquid temperature detection means 11 for detecting the temperature of this sealing liquid is provided.
(P_1+ρ_dH) P_1: Storage tank internal pressure ρ_d: Design density of the measured liquid H: Height from the first pressure input part 1a to the measured liquid level (unknown) and the second pressure input part 1b (P_1+ρ_sh) ρ_s: Density of the sealing liquid h: The sealing liquid height calculated from the second pressure input part 1b is used to calculate the differential pressure ΔP between the two using the following formula (1) ΔP=(P_1+ρ_dH) )−(P_1+ρ_sh)=
ρ_dH−ρ_sh...(1) By adding ρ_sh to the right side of the equation (1) in advance in the differential pressure gauge 1, the differential pressure detection means 13 detects based on the following (ρ_s=ρ_s_0 at this time) △P
= ρ_dH... (2) The zero point adjustment means 30 calculates the liquid level H of the liquid to be measured from the obtained differential pressure using the following equation (3) H = ΔP/ρ_d... (3) The difference between the sealing liquid density ρ_s_0 at the time of zero point adjustment and the sealing liquid density ρ_s_a at the time of actual measurement is calculated using the following formula (4) ρ_s_a-ρ_s_0=β(t_a-t_0)...
4) β: Expansion coefficient of seal liquid/°C t_a: Seal liquid temperature at the time of measurement t_0: Fluctuation detection means 15 in seal liquid density determined from seal liquid temperature at zero point adjustment and liquid level calculation means 1
When calculating the liquid level height in step 2, the error pressure β (t_a-t_0) based on the variation in seal liquid density included in △P
A differential pressure type measuring device characterized by comprising an error correction means 31 for canceling h. [2] Equipped with a differential pressure gauge 1 that has a first pressure input section 1a and a second pressure input section 1b and measures the differential pressure between the pressures input to each of these pressure input sections (1a, 1b). The first pressure input part 1a of the pressure gauge 1 is connected to the storage tank 2 containing the measurement liquid through the first pipe 3, and the second pressure input part 1b of the differential pressure gauge 1 is connected to the storage tank 2 through the second pipe 4. The connection point between the second pipe 4 and the storage tank 2 is located at a higher position than the connection point between the first pipe 3 and the storage tank 2. Second
At least the second tube 4 of the tubes 4 is filled with a sealing liquid, and a sealing liquid temperature detection means 11 for detecting the temperature of this sealing liquid is provided.
(P_1+ρ_dH) P_1: Storage tank internal pressure ρ_d: Design density of the measured liquid H: Height from the first pressure input part 1a to the measured liquid level (unknown) and the second pressure input part 1b (P_1+ρ_sh) ρ_s: Density of sealing liquid h: The sealing liquid height calculated from the second pressure input part 1b, the differential pressure ΔP between the two is calculated by the following formula (1) ΔP=(P_1+ρ_dH) −(P_1+ρ_sh)=
ρ_dH−ρ_sh...(1) A differential pressure detection means 13 detects the pressure based on
By adding (ρ_s=ρ_s_0 at this time) Δ
P=ρ_dH...(2) The zero point adjustment means 30 and the liquid level height H of the liquid to be measured from the obtained differential pressure are calculated from the following equation (3) H=ΔP/ρ_d...(3) When calculating the liquid level height using the liquid level calculation means 12, the following formula (5) is used: ε=[-β(t_a-t_0)h]/(ρ_dH_m)
...(5) β: Expansion coefficient of sealing liquid / °C t_0: Seal liquid temperature at zero point adjustment t_a: Seal liquid temperature at measurement ρ_d: Design density of measured liquid (=fixed value) H_m: Measured liquid an error correction means 31 which calculates the zero point movement amount ε in the measurement range of the liquid level height and multiplies the obtained actual value calculated by the liquid level calculation means 12 by 1/(1+ε) to obtain the true value; A differential pressure measuring device equipped with [3] The value of h is calculated using the following equation (6) h=(-ΔP_0)/[ρ_s_1+β(t_0-t_
1)]...(6)ΔP_0: Differential pressure at zero point adjustment (=measured value) ρ_s_1: Sealing liquid density at any reference temperature (=fixed value) β: Sealing liquid expansion coefficient/°C (=fixed value ) t_0: sealing liquid temperature at the time of zero point adjustment (=measured value) t_1: arbitrary reference temperature (=fixed value) Pressure measuring device. [4] Equipped with a differential pressure gauge 1 that has a first pressure input section 1a and a second pressure input section 1b and measures the differential pressure between the pressures input to each of these pressure input sections (1a, 1b), The first pressure input part 1a of the pressure gauge 1 is connected to the storage tank 2 containing the measurement liquid through the first pipe 3, and the second pressure input part 1b of the differential pressure gauge 1 is connected to the storage tank 2 through the second pipe 4. The connection point between the second pipe 4 and the storage tank 2 is located at a higher position than the connection point between the first pipe 3 and the storage tank 2. Second
At least the second tube 4 of the tubes 4 is filled with a sealing liquid, and a sealing liquid temperature detection means 11 for detecting the temperature of this sealing liquid is provided. Pressure (P_1+ρ_L+ρHl) input to the first pressure input part 1a with the liquid to be measured placed in the storage tank 2 so that the liquid level is higher than the connection point.P_1: Storage tank internal pressure ρ: Density of the liquid to be measured (Unknown) L: Height from the connection point between the second pipe 4 and the storage tank 2 to the liquid level to be measured Hl: The connection point between the first pressure input part 1a and the second pipe 4 and the storage tank 2 and the pressure input to the second pressure input section 1b (P_1+ρL+ρ_sh) ρ_s: Density of the sealing liquid h: Sealed height of the sealing liquid calculated from the second pressure input section 1b (here, h=Hl) and a differential pressure detection means 13 that detects the differential pressure △P between the two based on the following equation (1)': △P = (P_1 + ρL + ρHl) - (P_1 + ρL + ρ_sh) = ρHl - ρ_sh = ρHl - ρ_sHl (1)'. , In the differential pressure gauge 1, ρ_sH is added to the right side of the equation (1)' in advance.
By adding l (at this time ρ_s=ρ_s_0)
The zero point adjustment means 30 sets ΔP=ρHl...(2)′, and the density ρ of the liquid to be measured is calculated from the obtained differential pressure using the following formula (8): ρ=ΔP/Hl...(8) The density calculating means 32 calculates the difference between the sealing liquid density ρ_s_0 at the time of zero point adjustment and the sealing liquid density ρ_s_a at the time of actual measurement using the following formula (4) ρ_s_a-ρ_s_0=β(ta-t_0) (4)
) β: Expansion coefficient of sealing liquid/°C t_a: Seal liquid temperature at the time of measurement t_0: Fluctuation detection means 15 in seal liquid density determined from seal liquid temperature at zero point adjustment and density calculation means 3
When calculating the liquid density in step 2, the error pressure β(t_a-t_0)h based on the variation in seal liquid density included in ΔP
A differential pressure type measuring device characterized by comprising an error correction means 31 for canceling the error. [5] Equipped with a differential pressure gauge 1 that has a first pressure input section 1a and a second pressure input section 1b and measures the differential pressure between the pressures input to each of these pressure input sections (1a, 1b), The first pressure input part 1a of the pressure gauge 1 is connected to the storage tank 2 containing the measurement liquid through the first pipe 3, and the second pressure input part 1b of the differential pressure gauge 1 is connected to the storage tank 2 through the second pipe 4. The connection point between the second pipe 4 and the storage tank 2 is located at a higher position than the connection point between the first pipe 3 and the storage tank 2. Second
At least the second tube 4 of the tubes 4 is filled with a sealing liquid, and a sealing liquid temperature detection means 11 for detecting the temperature of this sealing liquid is provided. Pressure (P_1+ρL+pHl) input to the first pressure input part 1a with the liquid to be measured placed in the storage tank 2 so that the liquid level is higher than the connection point (P_1+ρL+pHl) P_1: Internal pressure of the storage tank ρ: Density of the liquid to be measured (Unknown) L: Height from the connection point between the second pipe 4 and the storage tank 2 to the liquid level to be measured Hl: The connection point between the first pressure input part 1a and the second pipe 4 and the storage tank 2 and the pressure input to the second pressure input section 1b (P_1+ρL+p_sh) ρ_s: Density of the sealing liquid h: Sealed height of the sealing liquid calculated from the second pressure input section 1b (here, h=Hl) and a differential pressure detection means 13 that detects the differential pressure ΔP between the two based on the following equation (1)': ΔP = (P_1 + ρL + ρHl) - (P_1 + ρL + ρ_sh) = ρHl - ρ_sh = ρHl - ρ_sHl (1)'; In pressure gauge 1, ρ_sH is added to the right side of equation (1)' in advance.
By adding l (at this time ρ_s=ρ_s0)△
The zero point adjustment means 30 sets P=ρHl...(2)', and the density ρ of the liquid to be measured is calculated from the obtained differential pressure using the following formula (8): ρ=ΔP/Hl...(8) When calculating the liquid density using the density calculation means 32, the following (
9) Formula ε=[-β(t_a-t_0)h]/ρ_mHl・・(
9) β: Expansion coefficient of sealing liquid/°C t_a: Seal liquid temperature at the time of measurement t_0: Seal liquid temperature at the time of zero point adjustment ρ_m: Maximum value of the density measurement range of the liquid to be measured h: Second pressure input section 1b Sealing liquid height Hl calculated from: The zero point movement amount ε is calculated from the height from the first pressure input part 1a to the connection point between the second pipe 4 and the reservoir 2, and calculated by the density calculation means 32. A differential pressure type measuring device characterized in that it is equipped with an error correction means 31 configured to obtain a true value by multiplying the obtained actual measured value by 1/(1+ε).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2194389A JP2727513B2 (en) | 1989-01-31 | 1989-01-31 | Differential pressure measuring device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2194389A JP2727513B2 (en) | 1989-01-31 | 1989-01-31 | Differential pressure measuring device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH02201225A true JPH02201225A (en) | 1990-08-09 |
JP2727513B2 JP2727513B2 (en) | 1998-03-11 |
Family
ID=12069131
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2194389A Expired - Lifetime JP2727513B2 (en) | 1989-01-31 | 1989-01-31 | Differential pressure measuring device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2727513B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013088027A (en) * | 2011-10-18 | 2013-05-13 | Hitachi Plant Technologies Ltd | Cooling system and cooling method |
CN103308424A (en) * | 2013-06-30 | 2013-09-18 | 唐山三友氯碱有限责任公司 | Method for sodium hypochlorite density measurement and process control in chlorine recycle |
CN105486373A (en) * | 2016-01-19 | 2016-04-13 | 黄亮 | Liquid storage tank and liquid weight measuring method |
CN115307702A (en) * | 2022-09-07 | 2022-11-08 | 北京北方华创微电子装备有限公司 | Liquid parameter measuring device and method and semiconductor cleaning equipment |
-
1989
- 1989-01-31 JP JP2194389A patent/JP2727513B2/en not_active Expired - Lifetime
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013088027A (en) * | 2011-10-18 | 2013-05-13 | Hitachi Plant Technologies Ltd | Cooling system and cooling method |
CN103308424A (en) * | 2013-06-30 | 2013-09-18 | 唐山三友氯碱有限责任公司 | Method for sodium hypochlorite density measurement and process control in chlorine recycle |
CN103308424B (en) * | 2013-06-30 | 2015-12-23 | 唐山三友氯碱有限责任公司 | Sodium hypochlorite density measure during chlorine reclaims and course control method for use |
CN105486373A (en) * | 2016-01-19 | 2016-04-13 | 黄亮 | Liquid storage tank and liquid weight measuring method |
CN115307702A (en) * | 2022-09-07 | 2022-11-08 | 北京北方华创微电子装备有限公司 | Liquid parameter measuring device and method and semiconductor cleaning equipment |
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JP2727513B2 (en) | 1998-03-11 |
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