JP2012127710A - Differential pressure measurement method and device for the same - Google Patents
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
- G01M3/3281—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators removably mounted in a test cell
- G01M3/329—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators removably mounted in a test cell for verifying the internal pressure of closed containers
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
- G01M3/3236—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators by monitoring the interior space of the containers
- G01M3/3263—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators by monitoring the interior space of the containers using a differential pressure detector
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Abstract
Description
本発明は、差圧計測方法及び装置に関し、特に、マスター容器とワーク容器との内部の圧力差（差圧）に基づきワーク容器内の漏洩を判断する差圧計測方法及び装置に関する。 The present invention relates to a differential pressure measuring method and apparatus, and more particularly to a differential pressure measuring method and apparatus for determining leakage in a work container based on a pressure difference (differential pressure) inside a master container and a work container.
配管や容器などからの漏洩を検査する方法として、容器等の検査対象の内部を加圧又は減圧し、検査対象の内部圧力の変化を単圧式センサで測定し、その測定結果に基づき漏洩を判断することが行われている。 As a method for inspecting leaks from pipes and containers, pressurize or depressurize the inside of the test object such as a container, measure changes in the internal pressure of the test object with a single pressure sensor, and determine the leak based on the measurement results. To be done.
しかしながら、容器等が鋳造や溶接など熱処理が施された直後の状態のように、容器等それ自体が測定中に温度変化している場合や、検査中に環境温度が変化する場合など、検査対象の内部の気体の温度も変化している場合には、容器等の内部圧力は、温度変化の影響を受けて、容易に変動することとなり、精確な漏洩判断が難しくなる。特許文献１では、容器等の検査対象に対して大気圧状態での内部圧力の変化を測定して温度変化の影響を算出し、加圧又は減圧した際の内部圧力の変化から算出した温度変化の影響を除くことで、精確な漏洩検査を可能にする方法及び装置が提案されている。 However, if the container itself is changing in temperature during measurement, such as immediately after a heat treatment such as casting or welding, or if the environmental temperature changes during inspection, etc. When the temperature of the gas inside the container also changes, the internal pressure of the container or the like is easily changed under the influence of the temperature change, and it is difficult to accurately determine the leakage. In Patent Document 1, the change in internal pressure in an atmospheric pressure state is measured for an object to be inspected such as a container to calculate the effect of the temperature change, and the temperature change calculated from the change in internal pressure when the pressure is increased or decreased There has been proposed a method and apparatus that enables accurate leakage inspection by eliminating the influence of the above.
他方、漏洩を検査する方法には、特許文献２又は３に示すように、基準となる容器（以下、「マスター容器」という。）と検査対象となる配管や容器（以下、「ワーク容器」という。）との間に差圧センサを配置し、両者の差圧の変化に基づき、ワーク容器の漏洩を判断することが行われている。 On the other hand, as shown in Patent Document 2 or 3, the method for inspecting leakage includes a reference container (hereinafter referred to as “master container”) and a pipe or container to be inspected (hereinafter referred to as “work container”). )), And a leakage of the work container is determined based on a change in the differential pressure between them.
差圧センサは、単圧式センサと比較し、マスターとワークの双方を加圧し、それらの差圧を計測する方式であるため、計測範囲を狭くでき、その分、精度が高くなっている。このため、差圧センサを利用した漏洩検査方法及び装置への期待が高まっている。また、特許文献２又は３では、温度変化の影響を排除するため、大気圧状態における差圧の変化を測定し、テスト加圧状態における温度変化の影響を除去することが提案されている。 Since the differential pressure sensor is a system that pressurizes both the master and the workpiece and measures the differential pressure between them, compared with the single pressure sensor, the measurement range can be narrowed and the accuracy is increased accordingly. For this reason, the expectation to the leak test method and apparatus using a differential pressure sensor is increasing. Patent Document 2 or 3 proposes to measure the change in the differential pressure in the atmospheric pressure state and eliminate the influence of the temperature change in the test pressurization state in order to eliminate the effect of the temperature change.
近年、漏洩検査の作業効率の向上や検査精度の向上が求められている。しかしながら、例えば、漏洩検査対象となるワーク容器に対して、鋳造や溶接など熱処理が行われた直後に漏洩検査を行う場合には、精度の良い漏洩を実施するため、少なくとも数時間はワーク容器を室温に放置する必要があり、多くのワーク容器を効率的に漏洩検査する上での障害になっていた。 In recent years, improvement in work efficiency of leakage inspection and improvement in inspection accuracy have been demanded. However, for example, when performing a leak inspection immediately after a heat treatment such as casting or welding is performed on a work container to be subjected to a leak inspection, the work container is not removed for at least several hours in order to perform accurate leakage. It was necessary to leave it at room temperature, which was an obstacle to the efficient leakage inspection of many work containers.
また、特許文献２又は３における漏洩検査方法では、大気圧状態で測定した温度変化を、テスト加圧を行った状態における温度変化と仮定しているため、気体の状態違いや時間的なズレなどの影響が全く考慮されておらず、正確な漏洩検査を実現することが難しい。 Further, in the leakage inspection method in Patent Document 2 or 3, since the temperature change measured in the atmospheric pressure state is assumed to be the temperature change in the state where the test pressurization is performed, the gas state difference, temporal deviation, etc. Is not taken into account at all, and it is difficult to realize an accurate leak inspection.
本発明が解決しようとする課題は、上述したような問題を解決し、漏洩検査の作業効率を高め、漏洩検査の精度を向上させた差圧計測方法及び装置を提供することである。 The problem to be solved by the present invention is to provide a differential pressure measuring method and apparatus that solve the above-described problems, increase the work efficiency of the leak test, and improve the accuracy of the leak test.
上記課題を解決するため、請求項１に係る発明は、マスター容器とワーク容器との各々について、大気圧で気体を封止し、該マスター容器と該ワーク容器との間に発生する差圧値の変化を測定し温度補償値を求める温度補償値検出工程と、該マスター容器と該ワーク容器とに大気圧以外のテスト圧力を付与し、該マスター容器と該ワーク容器との間に発生する差圧値の変化を測定する差圧変化測定工程と、該差圧変化測定工程で測定した差圧値の変化を該温度補償値で補正し、その結果に基づき、該ワーク容器の漏洩を判断する差圧計測方法において、該ワーク容器のみの内部圧力に関する圧力変化を測定し、該温度補償値に係る差圧値の測定タイミングを決定する測定タイミング設定手段と、該マスター容器と該ワーク容器との間の差圧について、該温度補償値検出工程中に測定した大気圧に係る差圧値と、該差圧変化測定工程中に測定したテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、該温度補償値又は該差圧変化測定工程で測定した差圧値のいずれか一方を該密度変化により補正することを特徴とする。 In order to solve the above problems, the invention according to claim 1 is characterized in that, for each of the master container and the work container, the gas is sealed at atmospheric pressure, and the differential pressure value generated between the master container and the work container. A temperature compensation value detection step for measuring a change in temperature and obtaining a temperature compensation value; and applying a test pressure other than atmospheric pressure to the master container and the work container, and a difference generated between the master container and the work container A differential pressure change measurement step for measuring a change in pressure value, and a change in the differential pressure value measured in the differential pressure change measurement step is corrected with the temperature compensation value, and based on the result, leakage of the work container is determined. In the differential pressure measurement method, a measurement timing setting means for measuring a pressure change related to the internal pressure of only the work container and determining a measurement timing of the differential pressure value related to the temperature compensation value, and a master container and the work container Differential pressure between And determining a gas density change based on the differential pressure value related to the atmospheric pressure measured during the temperature compensation value detecting step and the differential pressure value related to the test pressure measured during the differential pressure change measuring step, Either the temperature compensation value or the differential pressure value measured in the differential pressure change measurement step is corrected by the density change.
請求項２に係る発明は、請求項１に記載の差圧計測方法において、該温度補償値検出工程は、該差圧変化測定工程の前後に行い、検出された前後の温度補償値に基づき、該差圧変化測定工程で測定した差圧値の変化を補正することを特徴とする。 The invention according to claim 2 is the differential pressure measurement method according to claim 1, wherein the temperature compensation value detection step is performed before and after the differential pressure change measurement step, and based on the detected temperature compensation values before and after, A change in the differential pressure value measured in the differential pressure change measuring step is corrected.
請求項３に係る発明は、請求項１又は２に記載の差圧計測方法において、該ワーク容器の容積が異なる場合でも、該マスター容器は容積が共通な容器を用いることを特徴とする。 The invention according to claim 3 is characterized in that, in the differential pressure measuring method according to claim 1 or 2, even if the volume of the work container is different, the master container uses a common volume.
請求項４に係る発明は、マスター容器と、ワーク容器と、該マスター容器と該ワーク容器との間の差圧を測定する差圧センサと、該マスター容器と該ワーク容器とを大気圧の気体で封止する大気圧調整手段と、該マスター容器と該ワーク容器とに大気圧以外のテスト圧力を付与するテスト圧力付与手段と、該大気圧調整手段を動作し該差圧センサの測定値に基づき温度補償値を求めると共に、該テスト圧力付与手段を動作し該差圧センサの測定値を該温度補償値で補正し、その結果に基づき、該ワーク容器の漏洩を判断する制御手段とを有する差圧計測装置において、該ワーク容器の内部圧力を測定するワーク容器内圧力測定手段を有し、該制御手段には、該ワーク容器内圧力測定手段の測定値に基づき、該温度補償値を測定する際の該差圧センサによる測定タイミングを決定すると共に、該ワーク容器内圧力測定手段から検出され、該大気圧調整手段の動作で得られる大気圧に係る差圧値と該テスト圧力付与手段の動作で得られるテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、該温度補償値又は該テスト圧力付与手段を動作し測定した差圧値のいずれか一方を該密度変化により補正するよう設定されていることを特徴とする。 According to a fourth aspect of the present invention, there is provided a master container, a work container, a differential pressure sensor for measuring a differential pressure between the master container and the work container, and the master container and the work container. The atmospheric pressure adjusting means for sealing with, the test pressure applying means for applying a test pressure other than atmospheric pressure to the master container and the work container, and the atmospheric pressure adjusting means are operated to obtain the measured value of the differential pressure sensor. And a control means for operating the test pressure applying means to correct the measured value of the differential pressure sensor with the temperature compensation value and determining leakage of the work container based on the result. The differential pressure measuring device has a work container pressure measuring means for measuring the internal pressure of the work container, and the control means measures the temperature compensation value based on the measured value of the work container pressure measuring means. The differential pressure when A measurement pressure by the sensor, and a pressure value detected by the pressure measuring means in the work container and obtained by the operation of the atmospheric pressure adjusting means and a test pressure obtained by the operation of the test pressure applying means. Based on the differential pressure value, the gas density change is obtained, and either the temperature compensation value or the differential pressure value measured by operating the test pressure applying means is corrected by the density change. It is characterized by that.
請求項５に係る発明は、請求項４に記載の差圧計測装置において、該マスター容器の内部圧力を測定するマスター容器内圧力測定手段を有し、該制御手段は、前記気体の密度変化を求める際に、該ワーク容器内圧力測定手段が測定する圧力値に代えて、該マスター容器内圧力測定手段による前記大気圧に係る差圧値及び前記テスト圧力に係る差圧値を用いるよう設定されていることを特徴とする。 According to a fifth aspect of the present invention, in the differential pressure measuring device according to the fourth aspect of the present invention, the apparatus includes a master container internal pressure measuring unit that measures the internal pressure of the master container, and the control unit measures the density change of the gas. When determining, instead of the pressure value measured by the work container internal pressure measuring means, the differential pressure value related to the atmospheric pressure and the differential pressure value related to the test pressure by the master container internal pressure measuring means are set to be used. It is characterized by.
請求項６に係る発明は、請求項４又は５に記載の差圧計測装置において、該テスト圧力付与手段により該マスター容器及び該ワーク容器にテスト圧力を付与する各々の配管経路は、等価な有効断面積を持つ絞りとなるように、配管経路上の開口断面積や長さが設定されていることを特徴とする。 The invention according to claim 6 is the differential pressure measuring device according to claim 4 or 5, wherein each piping path for applying test pressure to the master container and the work container by the test pressure applying means is equivalently effective. The opening cross-sectional area and the length on the piping path are set so that the aperture has a cross-sectional area.
請求項１に係る発明により、ワーク容器がマスター容器と異なる温度影響を受けた場合でも、ワーク容器のみの内部圧力に関する圧力変化を測定し、該温度補償値に係る差圧値の測定タイミングを決定する測定タイミング設定手段を有するため、マスター容器との温度差をなるべく少なくすることによって、検査に係る測定タイミングを最適化でき、漏洩検査の作業効率を向上させることが可能となる。例えば、ワーク容器内の温度変化が下降状態に安定している状況では、いつでも漏洩検査が可能であるため、ワーク容器の温度が完全に落ち着き、差圧も一定変化になるまでの数時間も検査を待つ必要が無い。 According to the invention according to claim 1, even when the work container is affected by a temperature different from that of the master container, the pressure change related to the internal pressure of only the work container is measured, and the measurement timing of the differential pressure value related to the temperature compensation value is determined. Since the measurement timing setting means is provided, the measurement timing related to the inspection can be optimized by reducing the temperature difference with the master container as much as possible, and the work efficiency of the leakage inspection can be improved. For example, in a situation where the temperature change in the work container is stable in a lowered state, it is possible to inspect the leak at any time, so the work container temperature is completely settled and the test is performed for several hours until the differential pressure changes to a constant value. There is no need to wait.
また、マスター容器又はワーク容器のいずれか一方の内部圧力について、温度補償値検出工程中に測定した大気圧に係る差圧値と、差圧変化測定工程中に測定したテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、温度補償値又は差圧変化測定工程で測定した差圧値のいずれか一方を該密度変化により補正するため、大気圧状態とテスト圧力状態との間の気体の密度変化を補完し、より精度の高い漏洩検査を行うことが可能となる。 Also, for the internal pressure of either the master container or the work container, the differential pressure value related to the atmospheric pressure measured during the temperature compensation value detection process and the differential pressure value related to the test pressure measured during the differential pressure change measurement process Based on the above, the density change of the gas is obtained, and either the temperature compensation value or the differential pressure value measured in the differential pressure change measurement process is corrected by the density change. It is possible to complement the gas density change and perform a more accurate leak test.
請求項２に係る発明により、温度補償値検出工程は、差圧変化測定工程の前後に行い、検出された前後の温度補償値に基づき、該差圧変化測定工程で測定した差圧値の変化を補正するため、温度補償値検出工程と差圧変化測定工程との間の時間のズレにより、温度変化状態が変化している場合でも、差圧変化測定工程の前後の温度変化を観察しているため、より精度の高い温度補償を行うことが可能となる。しかも、温度が短時間で変化している場合でも、漏洩検査を行うことができ、検査の作業効率を高めることも可能となる。 According to the invention of claim 2, the temperature compensation value detection step is performed before and after the differential pressure change measurement step, and the change in the differential pressure value measured in the differential pressure change measurement step is based on the detected temperature compensation values before and after. Therefore, even if the temperature change state changes due to the time lag between the temperature compensation value detection process and the differential pressure change measurement process, observe the temperature change before and after the differential pressure change measurement process. Therefore, temperature compensation with higher accuracy can be performed. Moreover, even when the temperature changes in a short time, a leakage inspection can be performed, and the inspection work efficiency can be improved.
請求項３に係る発明により、ワーク容器の容積が異なる場合でも、マスター容器は容積が共通な容器を用いるため、ワーク容器の種類毎にマスター容器を交換する必要が無く、作業効率の低下を抑制することが可能となる。しかも、多数のマスター容器を準備する必要もなく、検査コストの増加も抑制できる。 According to the invention of claim 3, even when the work containers have different volumes, the master container uses a container having a common volume, so there is no need to replace the master container for each type of work container, and a reduction in work efficiency is suppressed. It becomes possible to do. In addition, it is not necessary to prepare a large number of master containers, and an increase in inspection costs can be suppressed.
請求項４に係る発明により、ワーク容器の内部圧力を測定するワーク容器内圧力測定手段を有し、制御手段には、該ワーク容器内圧力測定手段の測定値に基づき、温度補償値を測定する際の該差圧センサによる測定タイミングを決定するため、上述した請求項１に係る発明と同様に、検査に係る測定タイミングを最適化でき、漏洩検査の作業効率を向上させることが可能となる。 According to the fourth aspect of the present invention, the internal pressure measurement means for measuring the internal pressure of the work container is provided, and the control means measures the temperature compensation value based on the measurement value of the internal pressure measurement means for the work container. Since the measurement timing by the differential pressure sensor at the time is determined, the measurement timing related to the inspection can be optimized and the work efficiency of the leakage inspection can be improved as in the above-described invention according to claim 1.
しかも、ワーク容器内圧力測定手段から検出され、大気圧調整手段の動作で得られる大気圧に係る差圧値とテスト圧力付与手段の動作で得られるテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、温度補償値又はテスト圧力付与手段を動作し測定した差圧値のいずれか一方を該密度変化により補正するよう設定するため、上述した請求項１に係る発明と同様に、大気圧状態とテスト圧力状態との間の気体の密度変化を補完し、より精度の高い漏洩検査を行うことが可能となる。 Moreover, the gas is detected based on the differential pressure value related to the atmospheric pressure detected by the operation of the atmospheric pressure adjusting means and the differential pressure value related to the test pressure obtained by the operation of the test pressure applying means detected from the pressure measuring means in the work container. In order to obtain a change in density of the temperature and set so that either the temperature compensation value or the differential pressure value measured by operating the test pressure applying means is corrected by the density change, as in the invention according to claim 1 described above, It is possible to complement the gas density change between the atmospheric pressure state and the test pressure state, and perform a more accurate leak test.
請求項５に係る発明により、マスター容器の内部圧力を測定するマスター容器内圧力測定手段を有し、制御手段は、気体の密度変化を求める際に、ワーク容器内圧力測定手段が測定する圧力値に代えて、該マスター容器内圧力測定手段による前記大気圧に係る差圧値及び前記テスト圧力に係る差圧値を用いるよう設定されているため、ワーク容器よりもマスター容器の方がより正確に内部の圧力値を測定することができるため、気体の密度変化をより正確に算出することが可能となる。 According to the fifth aspect of the present invention, there is provided a master container pressure measuring means for measuring the internal pressure of the master container, and the control means measures the pressure value measured by the work container pressure measuring means when determining the gas density change. Instead, the master container is more accurate than the work container because it is set to use the differential pressure value related to the atmospheric pressure and the differential pressure value related to the test pressure by the pressure measuring means in the master container. Since the internal pressure value can be measured, a change in gas density can be calculated more accurately.
請求項６に係る発明により、テスト圧力付与手段によりマスター容器及びワーク容器にテスト圧力を付与する各々の配管経路は、等価な有効断面積を持つ絞りとなるように、配管経路上の開口断面積や長さが設定されているため、マスター容器やワーク容器への気体の充填や放出を、適切な流量で実施することができ、充填や放出に係る所要時間を短縮でき、漏洩検査の作業効率を向上させることが可能となる。 According to the invention of claim 6, the opening cross-sectional area on the piping path is such that each piping path for applying the test pressure to the master container and the work container by the test pressure applying means is a throttle having an equivalent effective sectional area. Since the length and length are set, the filling and discharging of gas into the master container and work container can be carried out at an appropriate flow rate, the time required for filling and discharging can be shortened, and the work efficiency of leak inspection Can be improved.
以下、本発明の差圧計測方法及び装置について、詳細に説明する。
図１は、本発明の差圧計測方法に使用される装置の一例を示す。差圧計測装置は、マスター容器（基準容器）と、ワーク容器と、該マスター容器と該ワーク容器との間の差圧を測定する差圧センサを有している。該マスター容器と該ワーク容器とを大気圧の気体で封止する大気圧調整手段として、マスター容器側バルブ（ＭＶ）とワーク容器側バルブ（ＷＶ）及び減圧用バルブが開かれる。さらに、該マスター容器と該ワーク容器とに大気圧以外のテスト圧力を付与するテスト圧力付与手段を備えている。テスト圧力付与手段としては、一例として、圧力源、調整器（レギュレータ）、供給用バルブ、及びマスター容器側バルブ（ＭＶ）とワーク容器側バルブ（ＷＶ）並びにこれらを接続する配管などから構成される。なお、ワーク容器には、容器だけでなく配管など、気体を収容可能な体積を有すると共に、密閉可能な構造を備え、漏洩検査が必要なものを意味する。また、本発明におけるテスト圧力は、大気圧以外の圧力に加圧及び減圧を行うことであり、以下では、加圧を中心に説明する。
Hereinafter, the differential pressure measuring method and apparatus of the present invention will be described in detail.
FIG. 1 shows an example of an apparatus used in the differential pressure measuring method of the present invention. The differential pressure measuring device includes a master container (reference container), a work container, and a differential pressure sensor that measures a differential pressure between the master container and the work container. As an atmospheric pressure adjusting means for sealing the master container and the work container with atmospheric gas, the master container side valve (MV), the work container side valve (WV), and the pressure reducing valve are opened. Furthermore, a test pressure applying means for applying a test pressure other than atmospheric pressure to the master container and the work container is provided. For example, the test pressure applying means includes a pressure source, a regulator (regulator), a supply valve, a master container side valve (MV) and a work container side valve (WV), and a pipe connecting them. . The work container means not only a container but also a pipe or the like having a volume capable of containing a gas and having a sealable structure and requiring a leakage inspection. The test pressure in the present invention is to perform pressurization and depressurization to a pressure other than atmospheric pressure, and the following description will focus on pressurization.
本発明の差圧計測装置では、ワーク容器の内部圧力を直接測定するため、ワーク容器内圧力測定手段（ＷＰ）を備えている。また、必要に応じて、マスター容器の内部圧力を測定するため、マスター容器内圧力測定手段（ＭＰ）を備えることも可能である。さらに、圧力源（加圧ポンプ）、レギュレータ、各種バルブは、不図示の制御手段によりコントロールされており、差圧センサやワーク容器内圧力測定手段（ＷＰ）やマスター容器内圧力測定手段（ＭＰ）からの検出信号は、該制御手段に入力され、必要な処理を施される。 In the differential pressure measuring device of the present invention, in order to directly measure the internal pressure of the work container, a work container internal pressure measuring means (WP) is provided. Moreover, in order to measure the internal pressure of a master container as needed, it is also possible to provide a master container internal pressure measurement means (MP). Further, the pressure source (pressure pump), regulator, and various valves are controlled by a control means (not shown), such as a differential pressure sensor, a work container pressure measurement means (WP), and a master container pressure measurement means (MP). The detection signal from is input to the control means and subjected to necessary processing.
（温度補償値の算出方法）
特許文献２又は３にも開示されているように、マスター容器とワーク容器とを大気圧状態で封止し、両者の差圧変化を観測し、温度影響を所定時間の差圧値変化（差圧値の時間変化量）として計測する。これを温度補償値とし、テスト圧力状態における差圧変化からこの温度補償値に相当する変化量を除去し、温度変化の影響を除いている。
(Temperature compensation value calculation method)
As disclosed in Patent Document 2 or 3, the master container and the work container are sealed in an atmospheric pressure state, a difference in pressure difference between the two is observed, and a temperature effect is measured by a change in the pressure difference value (difference in a predetermined time). It is measured as the amount of change in pressure value over time. This is used as a temperature compensation value, and the amount of change corresponding to this temperature compensation value is removed from the differential pressure change in the test pressure state to eliminate the influence of the temperature change.
図１の差圧計測装置を用いて、マスター容器とワーク容器とを大気圧状態にする手順は、まず、大気圧調整手段を動作して、マスター容器側バルブ（ＭＶ）とワーク容器側バルブ（ＷＶ）とを開き、さらに、減圧用バルブを開放し、マスター容器内及びワーク容器内の内部圧力を大気圧状態とする。そして、その後、減圧用バルブを閉じる。マスター容器内及びワーク容器内の内部圧力の差をなるべく少なくし、ワーク容器側に搭載している圧力センサより大気圧状態下における圧力計測を開始する。そして、その後、マスター容器側バルブ（ＭＶ)及びワーク容器側バルブ（ＷＶ）も閉じられ、マスター容器及びワーク容器を個別に大気圧で封止する作業が完了する。その後、バルブの閉止作業に伴う過渡的な反応があるが、その後、マスター容器自体又はワーク容器自体の温度変化に応じて、個々の圧力が変化し、それに伴い、両者の差圧値も変化する。この差圧値の変化を差圧センサで測定することで、所定時間（単位時間）における差圧値変化量を温度補償値として算出する。 The procedure for bringing the master container and the work container into the atmospheric pressure state using the differential pressure measuring device of FIG. 1 is as follows. First, the atmospheric pressure adjusting means is operated, and the master container side valve (MV) and the work container side valve ( WV) is opened, and the pressure reducing valve is opened, and the internal pressure in the master container and the work container is brought to the atmospheric pressure state. Thereafter, the pressure reducing valve is closed. The difference in internal pressure between the master container and the work container is reduced as much as possible, and pressure measurement under atmospheric pressure is started from the pressure sensor mounted on the work container side. Thereafter, the master container side valve (MV) and the work container side valve (WV) are also closed, and the operation of individually sealing the master container and the work container at atmospheric pressure is completed. After that, there is a transient reaction accompanying the valve closing operation, but then the individual pressure changes according to the temperature change of the master container itself or the work container itself, and the differential pressure value of both changes accordingly. . By measuring the change in the differential pressure value with a differential pressure sensor, the amount of change in the differential pressure value in a predetermined time (unit time) is calculated as a temperature compensation value.
（差圧値の測定タイミングの設定）
本発明の差圧計測方法及び装置の特徴は、測定タイミング設定手段として、マスター容器とワーク容器との差圧値の測定タイミングを、ワーク容器の内部圧力を直接計測し、その変化に基づいて設定していることである。ワーク容器の内部圧力を計測するワーク容器内圧力測定手段（ＷＰ）として、単圧式センサが利用可能である。
(Differential pressure value measurement timing setting)
The characteristic of the differential pressure measuring method and apparatus of the present invention is that, as a measurement timing setting means, the measurement timing of the differential pressure value between the master container and the work container is directly measured from the internal pressure of the work container and set based on the change. Is. A single pressure sensor can be used as a work container internal pressure measuring means (WP) for measuring the internal pressure of the work container.
従来、漏洩検査対象となるワーク容器が、鋳造や溶接などの熱処理を受けた直後では、容器自体の温度変化が激しいため、差圧式による精度の高い測定が困難であり、このため、少なくとも数時間は検査対象を室温に放置し、温度が安定するのを待っていた。これに対し、本発明の差圧計測方法では、ワーク容器内圧力測定手段で図２に示すように、ワーク容器内の内部圧力の変化を観測し、圧力変化が所定の状況（差圧測定しても支障のない状況）に達したことを確認し、差圧値の測定タイミングを発している。 Conventionally, immediately after a work container to be inspected for leakage is subjected to heat treatment such as casting or welding, the temperature change of the container itself is so severe that it is difficult to perform high-precision measurement by the differential pressure method. Left the test object at room temperature and waited for the temperature to stabilize. On the other hand, in the differential pressure measuring method of the present invention, as shown in FIG. 2, the work container internal pressure measuring means observes the change in the internal pressure in the work container, and the pressure change is in a predetermined condition (differential pressure measurement is performed. It is confirmed that it has reached the point where there is no problem, and the measurement timing of the differential pressure value is issued.
図２示すグラフのように、通常、ワーク容器内の内部圧力は一端は上昇し、下降傾向に転じる。この内圧の下降傾向は、容器の温度変化と内部の気体の温度変化が一致している期間であり、このような状態では、差圧値変化を測定しても、本発明が採用する温度補償値を利用して、十分精度の高い、漏洩による圧力変化を検出することが可能となる。 As shown in the graph of FIG. 2, the internal pressure in the work container usually rises at one end and turns downward. The decreasing tendency of the internal pressure is a period in which the temperature change of the container and the temperature change of the internal gas coincide with each other. In such a state, even if the pressure difference change is measured, the temperature compensation adopted by the present invention is used. By using the value, it becomes possible to detect a pressure change due to leakage with sufficiently high accuracy.
このように、ワーク容器内の内部圧力が下降傾向になるタイミングを、差圧値の測定タイミングとして設定することで、従来は、「現状の差圧式計測開始」で示すように、ワーク容器の温度変化が安定するまで数時間待機していたのを、「開発の差圧式計測開始」で示すように、数分後から測定が可能となる。このように、高温環境下におけるワーク容器を差圧式漏洩検査が開始できる待ち時間を短縮化でき、漏洩検査の作業効率を向上させることが可能となる。 In this way, by setting the timing at which the internal pressure in the work container tends to decrease as the measurement timing of the differential pressure value, the temperature of the work container has conventionally been set as shown in “Current differential pressure type measurement start”. As shown in "Development differential pressure type measurement start", it is possible to measure several minutes later, after waiting for several hours for the change to stabilize. Thus, the waiting time during which differential pressure type leakage inspection can be started on a work container in a high temperature environment can be shortened, and the work efficiency of leakage inspection can be improved.
（気体の密度変化に係る補正）
本発明の差圧計測方法及び装置の特徴は、マスター容器とワーク容器との間の差圧値を、大気圧状態とテスト圧力状態とで測定しているが、両者の状態の間には気体の密度の相違が存在する。このような気体の密度変化も考慮することにより、温度変化の影響をより正確に除去することが可能となる。
(Correction for gas density change)
A feature of the differential pressure measuring method and apparatus of the present invention is that a differential pressure value between a master container and a work container is measured in an atmospheric pressure state and a test pressure state. There are differences in density. Considering such a change in gas density, the influence of the temperature change can be more accurately removed.
大気圧の気体密度とテスト圧力状態の気体密度とでは、テスト圧力が充填された後の増加した空気量に対応する分だけ気体密度が変化している。そのため、密度変化に対応する補正係数を算出することで、従来の温度補償値やテスト圧力状態での差圧値を補正し、正確な漏洩量を検知できる。 The gas density at the atmospheric pressure and the gas density in the test pressure state change by an amount corresponding to the increased amount of air after the test pressure is filled. Therefore, by calculating the correction coefficient corresponding to the density change, it is possible to correct the conventional temperature compensation value and the differential pressure value in the test pressure state, and to detect an accurate leakage amount.
以下では、テスト圧力（例えば、45kPa(G)とする。）に対する密度補正係数の計算方法を示している。
理想気体の状態方程式ＰＶ＝ρＲθは、以下のようなパラメータを用いて定義される。
・Ｐ：圧力 [Pa]
・Ｖ：容器の容積 [m3]
・ρ：空気の密度 [kg/m3]
・Ｒ：ガス定数 [J/(kg . K)]
・θ：温度 [K]
In the following, a calculation method of the density correction coefficient for the test pressure (for example, 45 kPa (G)) is shown.
The ideal gas equation of state PV = ρRθ is defined using the following parameters.
・ P: Pressure [Pa]
・ V: Volume of container [m 3 ]
・ Ρ: Air density [kg / m 3 ]
・ R: Gas constant [J / (kg. K)]
・ Θ: Temperature [K]
上述した状態方程式から圧力は、Ｐ＝ρＲθ／Ｖで示される。温度補正を考慮した漏洩による差圧[kPa]は、テスト圧力状態（45kPa(G)）での差圧値（温度変化と漏洩による差圧値）から、大気圧調整状態（例：0kPa(G)）の差圧（温度変化による差圧値）[kPa]を差し引くことで表されるため、漏洩による差圧は、以下の式（１）で表現される。ここでは、マスター容器とワーク容器とが異なる温度影響下における場合を想定している。 From the above equation of state, the pressure is expressed as P = ρRθ / V. The differential pressure [kPa] due to leakage taking temperature correction into consideration is the atmospheric pressure adjustment state (eg 0 kPa (G) from the differential pressure value (differential pressure value due to temperature change and leakage) in the test pressure state (45 kPa (G)) )) Differential pressure (differential pressure value due to temperature change) [kPa] is subtracted, so the differential pressure due to leakage is expressed by the following equation (1). Here, it is assumed that the master container and the work container are under different temperature influences.
上記式（１）よりテスト圧力（45ｋPa（G））と大気圧とにおける気体の密度は、各々、ρ２及びρ１で定義される。これらの数値は、既知のものであり、例えば、以下のような数値となる。
・標準20℃にある大気圧の密度（ρ１）＝ 1.205 kg/m3
・標準20℃にあるテスト圧力（45kPa(G)）の密度（ρ２）＝ 1.740 kg/m3
なお、大気圧（容器内圧力0kPa(G)）を101.325 kPa（Abs）として計算している。
From the above equation (1), the gas densities at the test pressure (45 kPa (G)) and the atmospheric pressure are defined by ρ 2 and ρ 1 , respectively. These numerical values are known, and are as follows, for example.
・ Density of atmospheric pressure at standard 20 ℃ (ρ 1 ) = 1.205 kg / m 3
・ Density (ρ 2 ) of test pressure (45 kPa (G)) at 20 ° C = 1.740 kg / m 3
Note that the atmospheric pressure (the pressure in the container 0 kPa (G)) is calculated as 101.325 kPa (Abs).
大気圧測定時間帯とテスト圧力（45 kPa(G)）時の気密試験が同じ温度変化をしていると考え、補正係数を倍率で計算した場合には、大気圧状態の温度補償値の補正係数は、ρ２／ρ１で得られ、1.444となる。
よって、テスト圧力（45kPa(G)）気密試験の差圧値に対する温度補正量[kPa]は、大気圧状態の差圧（温度補償値）[kPa]に1.444を掛けたものとなる。
If it is assumed that the airtight test at the atmospheric pressure measurement time zone and the test pressure (45 kPa (G)) have the same temperature change, and the correction factor is calculated by the magnification, the correction of the temperature compensation value in the atmospheric pressure state The coefficient is obtained by ρ2 / ρ1, and is 1.444.
Accordingly, the temperature correction amount [kPa] for the differential pressure value of the test pressure (45 kPa (G)) airtight test is obtained by multiplying the differential pressure (temperature compensation value) [kPa] in the atmospheric pressure state by 1.444.
このように、大気圧とテスト圧力を測定することで、容易に気体密度に係る補正係数を算出することが可能である。本発明では、圧力の測定手段として、ワーク容器の内部圧力を測定するワーク容器内圧力測定手段（ＷＰ）を利用することが可能である。また、マスター容器の内部圧力を測定するマスター容器内圧力測定手段（ＭＰ）を別途設け、ワーク容器内圧力測定手段（ＷＰ）が測定する圧力値に代えて、該マスター容器内圧力測定手段（ＭＰ）により、マスター容器内の大気圧及びテスト圧力を測定しても良い。ワーク容器よりもマスター容器の方がより正確に内部の圧力値を測定することができるため、マスター容器内圧力測定手段を用いることで、気体の密度変化をより正確に算出することが可能となる。 Thus, by measuring the atmospheric pressure and the test pressure, it is possible to easily calculate the correction coefficient related to the gas density. In the present invention, it is possible to use a work container pressure measuring means (WP) for measuring the internal pressure of the work container as the pressure measuring means. Also, a master container pressure measuring means (MP) for measuring the internal pressure of the master container is separately provided, and instead of the pressure value measured by the work container pressure measuring means (WP), the master container pressure measuring means (MP) ) To measure the atmospheric pressure and the test pressure in the master container. Because the master container can measure the internal pressure value more accurately than the work container, it is possible to calculate the gas density change more accurately by using the pressure measurement means in the master container. .
（テスト圧力状態の前後における温度評価）
本発明の差圧計測方法及び装置では、温度補正を行う温度補償値の検出を、テスト圧力状態の前段階だけでなく、後段階でも行っている。これにより、テスト圧力状態における温度変化が、テスト圧力状態前の温度補償値を検出している際の温度変化から変化した場合でも、テスト圧力状態の前後で温度変化状態を判別するため、テスト圧力状態中の温度変化をより正確に判断することが可能となる。
(Temperature evaluation before and after test pressure)
In the differential pressure measuring method and apparatus of the present invention, the temperature compensation value for temperature correction is detected not only in the previous stage of the test pressure state but also in the subsequent stage. As a result, even when the temperature change in the test pressure state changes from the temperature change when the temperature compensation value before the test pressure state is detected, the test pressure state is determined before and after the test pressure state. It becomes possible to judge the temperature change during the state more accurately.
図３は、温度変化による差圧値ΔＰが変化する様子を、模式的に描いたグラフであり、テスト圧力状態（加圧［テスト圧］）の前後で、マスター容器及びワーク容器を大気圧状態に設定し、差圧値の時間変化を計測することで温度影響を評価している。温度影響を表す温度補償値は、大気圧状態での所定時間（単位時間）当たりの差圧値の変化量であるため、テスト圧力状態の前後で測定した温度補償値（図３の曲線の傾き）から、テスト圧力状態の温度変化が、正確に推定される。通常は、前後の計測の平均値を利用することができる。仮に、大気圧状態で温度影響を評価したタイミングとテスト圧力状態で差圧を計測したタイミングとの時間間隔が、前後で異なる場合には、当該時間間隔を考慮して加重平均することも可能である。 FIG. 3 is a graph schematically showing how the differential pressure value ΔP changes due to a temperature change. The master container and the work container are in an atmospheric pressure state before and after the test pressure state (pressurization [test pressure]). The temperature effect is evaluated by measuring the time variation of the differential pressure value. Since the temperature compensation value representing the temperature effect is the amount of change in the differential pressure value per predetermined time (unit time) in the atmospheric pressure state, the temperature compensation value measured before and after the test pressure state (the slope of the curve in FIG. 3). ), The temperature change in the test pressure state is accurately estimated. Usually, the average value of the measurement before and after can be used. If the time interval between the timing at which the temperature effect is evaluated in the atmospheric pressure state and the timing at which the differential pressure is measured in the test pressure state is different between before and after, it is possible to perform a weighted average considering the time interval. is there.
図４は、図３のようにテスト圧力状態の前後で温度変化の影響を評価した際のマスター容器とワーク容器との差圧の時間変化を示すグラフである。時間帯Ａでは、テスト圧力状態の前段階で温度影響を評価しており、マスター容器及びワーク容器内は大気圧状態に設定される。大気圧状態での計測開始前に差圧センサは、０点調整を行っている。温度が上昇している場合には、点線のように上昇傾向を示す。 FIG. 4 is a graph showing the change over time in the differential pressure between the master container and the work container when the influence of the temperature change is evaluated before and after the test pressure state as shown in FIG. In the time zone A, the temperature influence is evaluated in the previous stage of the test pressure state, and the master container and the work container are set to the atmospheric pressure state. The differential pressure sensor performs zero point adjustment before starting measurement in the atmospheric pressure state. When the temperature is rising, it shows an upward trend as shown by a dotted line.
次に、時間帯Ｂでは、テスト圧力状態中でのマスター容器とワーク容器との間の差圧の変化を示しており、漏洩や温度変化がある場合には、点線のように傾きを持つグラフが出現する。マスター容器とワーク容器とを対比すると、容積、熱伝達率、温度等のわずかな不均衡が原因となり、テスト圧力を充填後（加圧後）の差圧は、０点からずれる。例えば、加圧後の開始差圧値は10Pa〜40Pa程度となる。ただし、漏洩計測は、時間経過による差圧変化を計算するため、０点からのずれは全く問題ない。 Next, in the time zone B, the change in the differential pressure between the master container and the work container in the test pressure state is shown, and when there is a leakage or a temperature change, a graph with a slope as shown by a dotted line Appears. When the master container and the work container are compared, the differential pressure after filling the test pressure (after pressurization) is deviated from 0 point due to slight imbalances such as volume, heat transfer rate, and temperature. For example, the starting differential pressure value after pressurization is about 10 Pa to 40 Pa. However, since leakage measurement calculates a change in differential pressure over time, there is no problem with deviation from zero.
時間帯Ｃは、基本的には、時間帯Ａと同様である。なお、測定が可能となる開始時間までの期間で、差圧変化状態が安定するまでの期間を「整定時間」とし、「整定時間」の終わり（測定開始タイミング）を、図４のグラフ中に「整定」と表示している。 The time zone C is basically the same as the time zone A. The period until the start time when measurement is possible and the period until the differential pressure change state is stabilized is settling time, and the end of the settling time (measurement start timing) is shown in the graph of FIG. “Settling” is displayed.
（流量特性の改善）
本発明の差圧計測装置では、テスト圧力付与手段によりマスター容器及びワーク容器にテスト圧力を付与する各々の配管経路は、等価な有効断面積を持つ絞りとなるように、配管経路上の開口断面積や長さが設定されていることを特徴としている。
(Improvement of flow characteristics)
In the differential pressure measuring apparatus of the present invention, each pipe path for applying the test pressure to the master container and the work container by the test pressure applying means is a throttle having an equivalent effective cross-sectional area. The area and length are set.
マスター容器やワーク容器に気体を効率良く充填又は放出させることで、整定時間を短縮することが可能である。これにより、大気圧状態やテスト圧力状態における差圧値の測定の待ち時間を短くでき、漏洩検査の作業効率を向上させることが可能となる。マスター容器等に至る気体の移動経路には、配管・チューブや電磁弁などが介在しており、気体の流入又は放出する際の気体の流量は、使用する配管の口径や電磁弁の口径に左右される。 It is possible to shorten the settling time by efficiently filling or releasing the gas in the master container or the work container. Thereby, the waiting time for the measurement of the differential pressure value in the atmospheric pressure state or the test pressure state can be shortened, and the work efficiency of the leakage inspection can be improved. Pipes, tubes, solenoid valves, etc. are interposed in the gas movement path to the master container, etc., and the gas flow rate when the gas flows in or out depends on the diameter of the pipe used and the diameter of the solenoid valve. Is done.
したがって、マスター容器及びワーク容器への気体の充填や放出を、共に短時間で実現するには、テスト圧力付与手段によりマスター容器及びワーク容器にテスト圧力を付与する各々の配管経路に沿って、互いに等価な有効断面積を持つことが必要である。このため、配管口径や電磁弁口径などを全て同じにすることが理想ではあるが、少なくともこれらの配管経路を一つの絞りに置き換えた場合の有効断面積をマスター容器側とワーク容器側で同じにするよう設定することが好ましい。 Therefore, in order to achieve both filling and releasing of the gas into and from the master container and the work container in a short time, along the respective piping paths that apply the test pressure to the master container and the work container by the test pressure applying means. It is necessary to have an equivalent effective area. For this reason, it is ideal to make all the pipe diameters and solenoid valve diameters the same, but at least the effective cross-sectional area when these pipe paths are replaced with one throttle is the same on the master container side and the work container side. It is preferable to set so as to.
非チョーク流れを前提にすると、質量流量Ｇ[kg/s]は、次式（２）で表現することが可能である。なお、各記号は以下のような内容を意味する。
・Ｓｅ：縮流部の断面積及び有効断面積。縮流係数×Ａ０で表現できる。
・Ａ０：流路の実断面積及び電磁弁オリフィスの断面積[m2]。
オリフィスの内径ｄを利用してπｄ２／４で算出できる。
・Ｐ１：上流圧力[Pa]。上流圧力は容器内へ加圧する際にバルブ入り口付近の圧力である。
・Ｐ２：下流圧力[Pa]。下流圧力は充てんする前の容器内圧力（大気圧）
・θ１：上流温度（充てんする空気温度）[K]
・κ：空気の比熱比
・Ｒ：ガス定数 [J/kg . K]
Assuming a non-choke flow, the mass flow rate G [kg / s] can be expressed by the following equation (2). Each symbol means the following contents.
· S e: cross-sectional area and the effective cross-sectional area of the vena contracta. It can be expressed by contraction coefficient × A 0.
A 0 : actual cross-sectional area of the flow path and cross-sectional area [m 2 ] of the solenoid valve orifice.
It can be calculated by [pi] d 2/4 by utilizing the internal diameter d of the orifice.
· P 1: upstream pressure [Pa]. The upstream pressure is the pressure near the valve inlet when pressurizing the container.
· P 2: downstream pressure [Pa]. The downstream pressure is the pressure inside the container before filling (atmospheric pressure)
・ Θ 1 : upstream temperature (filled air temperature) [K]
・ Κ: Specific heat ratio of air ・ R: Gas constant [J / kg. K]
上記式（２）が示すように、気体の流量である質量流量Ｇは、有効断面積Ｓｅに比例しており、マスター容器側とワーク容器側とで当該有効断面積を等価にするよう、配管経路上の開口断面積や長さが選定されている。 As shown above equation (2) is the mass flow rate G is the flow rate of the gas is proportional to the effective area S e, to the equivalent of the effective area in the master container side and the workpiece container side, The opening cross-sectional area and length on the piping path are selected.
また、図５及び図６に示すように、気体の充填時間は、その後の整定時間に影響を与える。図５は、マスター容器又はワーク容器の内部圧力を単圧式センサで測定したグラフであり、大気圧からテスト圧力（漏洩計測に必要な圧力）に加圧し、その後、大気圧まで減圧した様子を示している。充填時間を０．３秒（実線）、０．５秒（点線）、２秒（一点鎖線）の３段階で、状態方程式を利用して数値計算（シミュレーション）を行った結果を示している。また、前提として、以下のような条件を設定している。
・電磁弁の有効断面積：2.75×10-8m2
・容積[V]： 0.00026m3
・空気と配管壁管の熱伝達面積[Sh]： 0.065m2
・加圧量[P]：201325 Pa(Abs)
・定容比熱[Cv]： 717[J/(kg. K)]
・定圧比熱 [Cp]： 1007[J/(kg. K)]
・ガス定数[R]： 287.1[J/(kg . K)]
・室温[θα]： 299.75[K]
・熱伝達率[h]： 30[W/(m2.K)]
Also, as shown in FIGS. 5 and 6, the gas filling time affects the subsequent settling time. Fig. 5 is a graph of the internal pressure of the master container or work container measured with a single pressure sensor, showing the pressure from atmospheric pressure to the test pressure (pressure required for leakage measurement) and then depressurizing to atmospheric pressure. ing. The result of numerical calculation (simulation) using a state equation in three stages of filling time of 0.3 seconds (solid line), 0.5 seconds (dotted line), and 2 seconds (one-dot chain line) is shown. As a premise, the following conditions are set.
-Effective sectional area of solenoid valve: 2.75 × 10 -8 m 2
・ Volume [V]: 0.00026m 3
・ Heat transfer area of air and pipe wall pipe [S h ]: 0.065m 2
・ Pressurization [P]: 201325 Pa (Abs)
-Constant volume specific heat [C v ]: 717 [J / (kg. K)]
・ Constant pressure specific heat [C p ]: 1007 [J / (kg. K)]
・ Gas constant [R]: 287.1 [J / (kg. K)]
・ Room temperature [θ α ]: 299.75 [K]
・ Heat transfer coefficient [h]: 30 [W / (m 2 .K)]
充填時間が短いほど、整定時間が短くなることが容易に理解できる。このため、空気供給する際に通過する配管や電磁弁を等価な有効断面積の選定を重視することにより無駄時間なく、素早く容器内に気体の充填を行うことができる。 It can be easily understood that the shorter the filling time, the shorter the settling time. For this reason, by placing importance on the selection of an equivalent effective cross-sectional area for piping and electromagnetic valves that pass when air is supplied, the container can be quickly filled with gas without wasted time.
ただし、気体の充填途中に電磁弁を閉めた場合には、断熱変化による圧力低下が発生する。この傾向は、充填時間が短い程、圧力低下が大きくなるため。短時間の充填時間で作業する際には、レギュレータ等の制御弁にテスト圧力より少し高めの圧力量を供給する必要がある。 However, when the solenoid valve is closed during gas filling, a pressure drop due to adiabatic change occurs. This tendency is because the pressure drop increases as the filling time is shorter. When working with a short filling time, it is necessary to supply a pressure amount slightly higher than the test pressure to a control valve such as a regulator.
図６は、充填開始から電磁弁を閉めた後の圧力低下の様子を、差圧値の変化で示したものである。図６からも充填時間が短い程、整定時間が短くなっていることが容易に理解される。なおこの傾向は、図５からも明らかなように、充填時よりも放出時の方が整定時間を短縮効果が顕著になっている。これは、充填時間に対応して有効断面積を確保しているため、放出時も放出時間が短縮されることとなるためである。 FIG. 6 shows the state of pressure drop after the electromagnetic valve is closed from the start of filling, by the change of the differential pressure value. It can be easily understood from FIG. 6 that the shorter the filling time, the shorter the settling time. As is clear from FIG. 5, the effect of shortening the settling time is more remarkable at the time of discharge than at the time of filling. This is because the effective cross-sectional area is ensured corresponding to the filling time, and thus the discharging time is shortened even during discharging.
（共通マスター）
本発明の圧力計測方法及び装置では、ワーク容器の容積が異なる場合でも、マスター容器は容積が共通な容器を用いることを特徴としている。従来の問題として、差圧式漏洩検査対象のワーク容器は、用途によってさまざまな容積が使用され、差圧式漏洩検査をする場合には、ワーク容器と同様のサイズや容積のマスター容器を準備する必要があった。本発明を利用することで、マスター容器として複数種類のマスター容器を準備・保管することが不要となり、また、検査時のマスター容器の交換作業なども省略でき、検査コストを下げ、しかも漏洩検査の作業効率を向上させることが可能となっている。
(Common Master)
In the pressure measuring method and apparatus according to the present invention, even when the work containers have different volumes, the master container uses a container having a common volume. As a conventional problem, work containers for differential pressure leak inspection have various volumes depending on the application. When performing differential pressure leak inspection, it is necessary to prepare a master container of the same size and volume as the work container. there were. By using the present invention, it is not necessary to prepare and store a plurality of types of master containers as master containers, and it is possible to omit the operation of replacing the master containers at the time of inspection, thereby reducing the inspection cost and leak inspection. Work efficiency can be improved.
気体の状態方程式を用いて、マスター容器とワーク容器との差圧ΔＰを表現すると、次式（３）となる。ただし、Ｗｍはマスター容器内の気体質量[kg]、Ｗｗはワーク容器内の気体質量[kg]、Ｒはガス定数[m2 / (s2 ．K)]、θは温度[K]、Ｖｍはマスター容器の容積[m3]、そしてＶｗはワーク容器の容積[m3]である。 When the differential pressure ΔP between the master container and the work container is expressed using the gas state equation, the following expression (3) is obtained. Where Wm is the gas mass [kg] in the master container, Ww is the gas mass [kg] in the work container, R is the gas constant [m 2 / (s 2 .K)], θ is the temperature [K], Vm Is the volume [m 3 ] of the master container, and Vw is the volume [m 3 ] of the work container.
上記式（数３）のように、マスター容器とワーク容器の容積が同じ場合には、温度が等しく同じ気体質量が入っている場合には、差圧ΔＰは０となる。このため、マスター容器とワーク容器の容積が異なる場合には、気体を急速に充填するなど、気体の動特性（各容器内における気体質量の時間変化）にも大きく依存し、必ずしも差圧ΔＰは０とはならない。 As in the above equation (Equation 3), when the volumes of the master container and the work container are the same, the differential pressure ΔP is 0 when the temperatures are the same and the same gas mass is contained. For this reason, when the volumes of the master container and the work container are different from each other, it depends greatly on the gas dynamic characteristics (change in gas mass with time in each container), such as rapidly filling the gas, and the differential pressure ΔP is not necessarily It will not be 0.
また、図７に示すように、整定時間に生じる差圧は、気体充填によりマスター容器とワーク容器との間のわずかな熱伝達率、温度影響、容積の違いなどにより異なる。大気圧で最初に差圧を計測することで容積変化により差圧が生じ、その分、密度係数を掛けることで補正を行うことが可能である。 Further, as shown in FIG. 7, the differential pressure generated during the settling time varies depending on the slight heat transfer coefficient between the master container and the work container, temperature influence, volume difference, and the like due to gas filling. By first measuring the differential pressure at atmospheric pressure, a differential pressure is generated due to the volume change, and correction can be made by multiplying that amount by the density coefficient.
また、計測途中に急激な温度影響を受けた場合には容積差による差圧に影響を与えるが、室温変化程度ではそれほど大きな影響はない。したがって、マスター容器とワーク容器との間で容積が異なっても、ワーク容器の漏洩発生（気体質量の時間的減少）による差圧のみが検出される。つまり、図７に示すように、マスター容器とワーク容器との間の容積の差に起因して、整定時間が若干は伸びる可能性があるが、大幅に伸びることはない。このため、整定時間経過後に差圧値の測定を行うことで、マスター容器とワーク容器との容積が異なる場合でも十分に漏洩検査が可能である。さらに、加圧後の差圧を０とする必要が無いことから、計測時間を短縮するため、充填後にマスター容器とワーク容器とを個々に遮断して、整定時間を待つよう構成することも可能である。 In addition, when the temperature is suddenly affected during the measurement, the pressure difference due to the volume difference is affected. Therefore, even if the volume differs between the master container and the work container, only the differential pressure due to the occurrence of leakage of the work container (time decrease in gas mass) is detected. That is, as shown in FIG. 7, the settling time may slightly increase due to the difference in volume between the master container and the work container, but it does not increase significantly. For this reason, by performing the measurement of the differential pressure value after the settling time has elapsed, even when the master container and the work container have different volumes, a leakage inspection can be sufficiently performed. Furthermore, since there is no need to set the differential pressure after pressurization to 0, the master container and work container can be individually shut off after filling and the settling time can be waited to shorten the measurement time. It is.
マスター容器の容積は、ワーク容器の容積より小さい方が、マスター容器側の整定時間が短く、漏洩検査を短時間で行う上では好ましい。しかも、上述したように各容器への配管経路に係る有効断面積を、両者が同じになるよう設定することで、マスター容器側の整定時間がワーク容器側より長くなることを、抑制することが可能となる。しかも、マスター容器の選定はワーク容器と同材質、同形状であることが望ましい。例えば、ワーク容器について、材質を銅、配管口径を10mm、容積を3リットルとした場合、マスター容器については、材質を銅、配管口径を10mm、容積は1リットルを選定する。 The volume of the master container is preferably smaller than the volume of the work container in order to perform a leak test in a short time because the settling time on the master container side is short. Moreover, as described above, by setting the effective cross-sectional area related to the piping path to each container so that both are the same, it is possible to suppress the settling time on the master container side from being longer than that on the work container side. It becomes possible. Moreover, the master container is preferably selected from the same material and shape as the work container. For example, if the work container is made of copper, the pipe diameter is 10 mm, and the volume is 3 liters, the master container is made of copper, the pipe diameter is 10 mm, and the volume is 1 liter.
なお、マスター容器の容積は、ワーク容器の容積の３分の１以上に設定することが好ましい。これは、マスター容器の容積が、ワーク容器の容積より極端に小さくなると、漏洩判断する時に静圧状態における空気の質量変化が大きく、誤判定をする場合がある。つまり、マスター容器とワーク容器との容積の差が大きいと、両者が受ける環境温度影響により差がより大きくなる。このように、同じ環境温度変化を受けていても容積等により内部の変化状態が異なるため、マスター容器の容積は、ワーク容器の容積の３分の１以上が望ましい。 The volume of the master container is preferably set to one third or more of the volume of the work container. If the volume of the master container is extremely smaller than the volume of the work container, the mass change of the air in the static pressure state is large when making a leak determination, and an erroneous determination may be made. That is, if the volume difference between the master container and the work container is large, the difference becomes larger due to the environmental temperature effect on both. As described above, since the internal change state varies depending on the volume or the like even when the same environmental temperature change is received, the volume of the master container is desirably one third or more of the volume of the work container.
以上説明したように、本発明によれば、漏洩検査の作業効率を高め、漏洩検査の精度を向上させた差圧計測方法及び装置を提供することが可能となる。 As described above, according to the present invention, it is possible to provide a differential pressure measuring method and apparatus that enhances the work efficiency of the leak test and improves the accuracy of the leak test.
気体の状態方程式を用いて、マスター容器とワーク容器との差圧ΔＰを表現すると、次式（３）となる。ただし、Ｗｍはマスター容器内の気体質量[kg]、Ｗｗはワーク容器内の気体質量[kg]、Ｒはガス定数[J/(kg . K)]、θは温度[K]、Ｖｍはマスター容器の容積[m3]、そしてＶｗはワーク容器の容積[m3]である。
When the differential pressure ΔP between the master container and the work container is expressed using the gas state equation, the following expression (3) is obtained. Where Wm is the gas mass [kg] in the master container, Ww is the gas mass [kg] in the work container, R is the gas constant [ J / (kg. K) ], θ is the temperature [K], and Vm is the master. The volume [m 3 ] of the container, and Vw is the volume [m 3 ] of the work container.
上記課題を解決するため、請求項１に係る発明は、マスター容器とワーク容器との各々について、大気圧で気体を封止し、該マスター容器と該ワーク容器との間に発生する差圧値の変化を測定し温度補償値を求める温度補償値検出工程と、該マスター容器と該ワーク容器とに大気圧以外のテスト圧力を付与し、該マスター容器と該ワーク容器との間に発生する差圧値の変化を測定する差圧変化測定工程と、該差圧変化測定工程で測定した差圧値の変化を該温度補償値で補正し、その結果に基づき、該ワーク容器の漏洩を判断する差圧計測方法において、該ワーク容器のみの内部圧力に関する圧力変化を測定し、該温度補償値に係る差圧値の測定タイミングを決定する測定タイミング設定手段を有すると共に、該マスター容器と該ワーク容器との間の差圧について、該温度補償値検出工程中に測定した大気圧に係る差圧値と、該差圧変化測定工程中に測定したテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、該温度補償値又は該差圧変化測定工程で測定した差圧値のいずれか一方を該密度変化により補正することを特徴とする。 In order to solve the above problems, the invention according to claim 1 is characterized in that, for each of the master container and the work container, the gas is sealed at atmospheric pressure, and the differential pressure value generated between the master container and the work container. A temperature compensation value detection step for measuring a change in temperature and obtaining a temperature compensation value; and applying a test pressure other than atmospheric pressure to the master container and the work container, and a difference generated between the master container and the work container A differential pressure change measurement step for measuring a change in pressure value, and a change in the differential pressure value measured in the differential pressure change measurement step is corrected with the temperature compensation value, and based on the result, leakage of the work container is determined. In the differential pressure measurement method, the apparatus has measurement timing setting means for measuring a pressure change related to the internal pressure of only the work container and determining a measurement timing of the differential pressure value related to the temperature compensation value, and the master container and the work container When As for the differential pressure between them, the gas density change based on the differential pressure value related to the atmospheric pressure measured during the temperature compensation value detection step and the differential pressure value related to the test pressure measured during the differential pressure change measurement step And either the temperature compensation value or the differential pressure value measured in the differential pressure change measuring step is corrected by the density change.
Claims (6)
該マスター容器と該ワーク容器とに大気圧以外のテスト圧力を付与し、該マスター容器と該ワーク容器との間に発生する差圧値の変化を測定する差圧変化測定工程と、
該差圧変化測定工程で測定した差圧値の変化を該温度補償値で補正し、その結果に基づき、該ワーク容器の漏洩を判断する差圧計測方法において、
該ワーク容器のみの内部圧力に関する圧力変化を測定し、該温度補償値に係る差圧値の測定タイミングを決定する測定タイミング設定手段と、
該マスター容器と該ワーク容器との間の差圧について、該温度補償値検出工程中に測定した大気圧に係る差圧値と、該差圧変化測定工程中に測定したテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、該温度補償値又は該差圧変化測定工程で測定した差圧値のいずれか一方を該密度変化により補正することを特徴とする差圧計測方法。 Temperature compensation value detection step for obtaining a temperature compensation value by sealing a gas at atmospheric pressure for each of the master container and the work container and measuring a change in the differential pressure value generated between the master container and the work container When,
Applying a test pressure other than atmospheric pressure to the master container and the work container, and measuring a change in differential pressure value generated between the master container and the work container;
In the differential pressure measurement method of correcting the change of the differential pressure value measured in the differential pressure change measurement step with the temperature compensation value, and determining leakage of the work container based on the result,
A measurement timing setting means for measuring a pressure change related to the internal pressure of only the work container and determining a measurement timing of the differential pressure value related to the temperature compensation value;
Regarding the differential pressure between the master vessel and the work vessel, the differential pressure value related to the atmospheric pressure measured during the temperature compensation value detection step and the differential pressure related to the test pressure measured during the differential pressure change measurement step A differential pressure measurement method characterized by obtaining a gas density change based on the value and correcting either the temperature compensation value or the differential pressure value measured in the differential pressure change measurement step by the density change.
該ワーク容器の内部圧力を測定するワーク容器内圧力測定手段を有し、
該制御手段には、該ワーク容器内圧力測定手段の測定値に基づき、該温度補償値を測定する際の該差圧センサによる測定タイミングを決定すると共に、該ワーク容器内圧力測定手段から検出され、該大気圧調整手段の動作で得られる大気圧に係る差圧値と該テスト圧力付与手段の動作で得られるテスト圧力に係る差圧値とに基づき、気体の密度変化を求め、該温度補償値又は該テスト圧力付与手段を動作し測定した差圧値のいずれか一方を該密度変化により補正するよう設定されていることを特徴とする差圧計測装置。 A master container, a work container, a differential pressure sensor for measuring a differential pressure between the master container and the work container, and an atmospheric pressure adjusting means for sealing the master container and the work container with an atmospheric pressure gas And a test pressure applying means for applying a test pressure other than atmospheric pressure to the master container and the work container, and operating the atmospheric pressure adjusting means to obtain a temperature compensation value based on the measured value of the differential pressure sensor, In the differential pressure measuring device having the control means for operating the test pressure applying means, correcting the measured value of the differential pressure sensor with the temperature compensation value, and judging leakage of the work container based on the result,
A work container internal pressure measuring means for measuring the internal pressure of the work container;
The control means determines the measurement timing by the differential pressure sensor when measuring the temperature compensation value based on the measurement value of the work container internal pressure measurement means, and is detected from the work container internal pressure measurement means. Then, based on the differential pressure value related to the atmospheric pressure obtained by the operation of the atmospheric pressure adjusting means and the differential pressure value related to the test pressure obtained by the operation of the test pressure applying means, a change in gas density is obtained and the temperature compensation is performed. A differential pressure measuring device, wherein either one of the value or the differential pressure value measured by operating the test pressure applying means is corrected by the density change.
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| CN104677572A (en) * | 2013-12-03 | 2015-06-03 | 宜兴市四通家电配件有限公司 | Proton exchange membrane fuel cell bipolar plate leak detection method and device |
| CN111964836A (en) * | 2020-07-22 | 2020-11-20 | 歌尔科技有限公司 | Barometer calibration method and device and electronic equipment |
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| US11781936B2 (en) | 2019-10-04 | 2023-10-10 | Mitsubishi Electric Corporation | Airtightness evaluation device |
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| DE102013020388A1 (en) * | 2012-12-13 | 2014-06-18 | Tesat-Spacecom Gmbh & Co. Kg | Method for checking the density of a housing |
| CN104764560B (en) * | 2015-03-23 | 2018-01-05 | 凯龙高科技股份有限公司 | A kind of differential pressure pickup |
| CN110081944A (en) * | 2019-06-05 | 2019-08-02 | 浙江埃泰克环境科技有限公司 | A kind of gas measuring method and equipment therefor based on real-time pressure variation |
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