WO1998026266A1 - Procede permettant de determiner une acceptation/ un rejet d'un capteur de pression - Google Patents

Procede permettant de determiner une acceptation/ un rejet d'un capteur de pression Download PDF

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Publication number
WO1998026266A1
WO1998026266A1 PCT/JP1996/003601 JP9603601W WO9826266A1 WO 1998026266 A1 WO1998026266 A1 WO 1998026266A1 JP 9603601 W JP9603601 W JP 9603601W WO 9826266 A1 WO9826266 A1 WO 9826266A1
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WO
WIPO (PCT)
Prior art keywords
pressure
voltage
sensor
vacuum
discharge
Prior art date
Application number
PCT/JP1996/003601
Other languages
English (en)
Japanese (ja)
Inventor
Toshihisa Matsui
Tomio Matsui
Masahiro Ueda
Atsuo Irisa
Original Assignee
Hokkei Industries L.T.D.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hokkei Industries L.T.D. filed Critical Hokkei Industries L.T.D.
Priority to PCT/JP1996/003601 priority Critical patent/WO1998026266A1/fr
Priority to PCT/JP1997/001627 priority patent/WO1998026267A1/fr
Publication of WO1998026266A1 publication Critical patent/WO1998026266A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L27/00—Testing or calibrating of apparatus for measuring fluid pressure
    • G01L27/007—Malfunction diagnosis, i.e. diagnosing a sensor defect
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • 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
    • G01M3/40—Investigating fluid-tightness of structures by using electric means, e.g. by observing electric discharges

Definitions

  • a strain gauge type pressure sensor is indispensable as a vacuum sensor for, for example, increasing the efficiency of an automobile engine.
  • This type of normal pressure sensor detects the pressure difference between the internal high vacuum area and the external pressure introduction pipe by means of a piezoelectric element installed in a vacuum insulated manner between the two. The value is amplified as an electrical signal and extracted.
  • the degree of vacuum inside the container during manufacturing is usually 6.7 Pa (0.05 Torr) or less, and the durability of the vacuum sensor is 20 years or more. That is, it is said that the maximum permissible vacuum leak rate of this kind of pressure sensor that is put into practical use must be less than 1.0 X 10 ⁇ —5 ⁇ Pa ⁇ ccZ seconds.
  • the current general inspection method is to enclose the pressure sensor in a radioactive material autoclave for several days, and if a vacuum leak occurs, the radioactive gas is sucked. It is usually referred to as the “radicro method,” in which measurements are made at power supply or the like to determine the quality or vacuum leak rate.
  • the present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of the conventional determination method using radioactivity. Instead, it is possible to estimate practically a wide range from both discharge and electrical output characteristics for vacuum leaks and electrical circuit defects, and to determine the quality of pressure sensors easily, safely, accurately, non-polluting and economically.
  • the purpose is to provide. Disclosure of the invention
  • the present invention proposes a new method for measuring the internal pressure of a pressure sensor container as described above, and the present invention is based on, in principle, Paschen's law that the firing voltage depends on the degree of vacuum inside the container. Based on (Paschen's Law), it is possible to instantaneously measure the degree of vacuum inside a sensor container from the discharge starting voltage of the first pulse, and pass / fail without giving any change to the state inside the sensor container It proposes a method that can judge.
  • the method for judging the quality of a pressure sensor according to the present invention is based on a strain gauge type pressure sensor that measures pressure by a strain voltage generated from a difference between a degree of vacuum inside a sensor and a pressure applied to a pressure introducing unit. This is a method for determining whether or not leakage has occurred.
  • the positive electrode side of a power supply that generates a DC high voltage is connected to a terminal having all electrodes short-circuited through a resistor having a high resistance value, the sensor-one container is grounded, and the terminal and the cell are connected to each other.
  • the resistance value of this resistor is selected so that the discharge current does not destroy the circuit in the sensor-one container.
  • the principle adopted by the present invention for measuring the vacuum pressure of such a pressure sensor is Paschen's law as described above. As is well known, this law defines the minimum voltage required to cause a spark discharge as a function of the product of the distance between the electrodes and the pressure of the gas when the electric field is uniform and the temperature and humidity of the gas are constant. Is to be done. Use this rule Then, the vacuum leak rate is measured from the relationship between the discharge phenomenon and the pressure.
  • the pass / fail judgment method of the pressure sensor according to the present invention requires a certain period of time until the judgment can be made, but the degree of vacuum can be instantaneously measured from the discharge starting voltage of one discharge pulse. It is a completely new method that can measure without changing the internal state.
  • FIG. 1 is a plan sectional view (A) and a partial side sectional view (B) showing the structure of a pressure sensor 1 to be measured.
  • FIG. 2 is a conceptual diagram showing a measurement system according to the present invention of the pressure sensor of FIG.
  • FIG. 3 is a cross-sectional view conceptually showing a configuration of an experimental apparatus for verifying the present invention.
  • FIG. 4 is a graph showing a result of discharging by applying a voltage in the experimental apparatus of FIG.
  • FIG. 5 is a graph showing an enlarged part of FIG.
  • FIG. 6 is a waveform diagram showing a discharge pulse waveform due to voltage application in the experimental apparatus of FIG.
  • FIG. 7 is a graph showing the relationship between the number of days and the pressure change when a leak occurs at the allowable maximum leak rate.
  • the pressure sensor 11 includes a base 1a, a plurality of electrodes 2 and a pressure introduction pipe 3 provided electrically insulated from each other, a metal diaphragm 4 attached to a tip of the pressure introduction pipe 3, and a diaphragm 4
  • IC piezoelectric element and an IC circuit
  • wiring between the IC circuit 5 and the electrode 2, and the upper part of them is covered with the metal container 6.
  • the principle adopted by the present invention for measuring the vacuum pressure of the pressure sensor 1 is to measure the vacuum leak rate from the relationship between the discharge phenomenon and the pressure according to Paschen's law as described above. That is, since the vacuum pressure P 1 can be estimated from the discharge starting voltage or discharge current caused by the difference in vacuum pressure, the internal pressure P 1 at a certain time T 1 is measured, and after a certain period T (seconds), By measuring the pressure P 2 at this point, the average rate of pressure change R during this period is
  • a terminal 2a in which all the electrodes 2 of the pressure sensor 11 of FIG. 1 are short-circuited, is connected to a DC high-voltage power supply 8 via an external resistor 7,
  • the metal container 6 is grounded via an external resistor 9 and an ammeter (A meter) 10, and a storage oscilloscope 11 is connected so that the voltage at both ends of the external resistor 9 can be observed and the discharge starting voltage can be recorded.
  • the voltmeter 12 is connected so as to indicate the applied voltage V0 from the power supply 8.
  • the power supply 8 sets the maximum applied voltage so as to generate an actual discharge voltage Vs (usually several hundred to several thousand) between the electrodes 2 and 2 of the pressure sensor 1.
  • a computer 13 is connected to the power supply 8 as means for varying the output voltage.
  • an electromagnetic relay 14 that is turned off by one discharge current is connected to the negative electrode side of the power supply 8, and this is grounded.
  • the present invention makes it possible to estimate the internal pressure of one sensor and one container from one discharge pulse without affecting the inside of the pressure sensor as much as possible.
  • the discharge voltage and discharge current are detected as early as possible so that the discharge can be stopped instantaneously.
  • a high resistance value of about 50 ⁇ is used as the external resistance 7.
  • the discharge voltage between the terminal 2a and the metal container 6 drops by 500 V, and the discharge stops.
  • the discharge current Id naturally stops flowing, so that the voltage V 0 applied by the power supply 8 is applied again between the terminal 2 a and the metal container 6, and the next discharge can be started.
  • the discharge starting voltage itself does not depend at all on the size of the external resistor 7, and therefore, in practicing the present invention, it is necessary to actually connect and check resistors having various resistance values.
  • the output voltage of the power supply 8 can be changed in a desired form by the computer 13, and the voltage application from the power supply 8 is turned on and off by the electromagnetic relay 14.
  • a sharp rise in the applied voltage V 0 from the power supply 8 leads to large current discharge, that is, generation of a plurality of pulses in a short time.
  • the next discharge is performed.
  • the circuit is automatically opened by the electromagnetic relay 14 before a pulse occurs. If the electromagnet used for the electromagnetic relay 14 has, for example, a dead time of about 0.5 ms and a rise time of about 1 ms, a delay of 1.5 ms occurs before operation starts.
  • the increase control of the applied voltage V 0 from the power supply 8 is controlled by the computer 13 so as to correspond to this time delay.
  • the shape of the electron emitting surface is like a needle tip having a diameter of about several i ⁇ m, the above-described strength can be easily reached even at a voltage of several hundred V.
  • the end of the pin-shaped electrode 2 and the IC surrounded by the plurality of electrodes 2 and arranged at the center thereof are several 10 m or so. Since the metal wires are connected by a thin metal wire and the distance between such a metal wire and the inner surface of the metal container 6 is 1 mm or less, there is a high possibility that the field emission as described above will occur.
  • the electric field strength may be sufficiently different by an order of magnitude, and the electron emission is an exponential function of the electric field strength. Differently.
  • the metal container 6 is grounded, and a positive electrode is connected to the terminal 2 a where the electrode 2 is short-circuited so that electrons are emitted from the metal container 6 to the electrode 2. Is applied. That is, by stabilizing the discharge start state, in other words, stabilizing the discharge start voltage by causing the electron emission to occur on the inner surface of the flat metal container 6.
  • FIGS. 3 and 4 showing measurement results of the discharge starting voltage Vd and the discharge current Id when the pressure P1 in the metal container 6 is changed.
  • the pressure measurement experimental device is configured as shown in FIG. First, the metal container 6 is removed, and the electrode 2, the pressure introducing pipe 3, the diaphragm 4, and the IC circuit 5 are mounted on the base la. It is attached to an acrylic plate 20 with holes as shown in the figure using an adhesive such as an arral die, covered with a vacuum bell jar 21, and inserted into one through hole of the vacuum bell jar 21. A Pirani vacuum gauge 22 is connected, a rotary pump (not shown) is connected to the other through-hole via a cock 23, and another one of the through-holes is connected to outside air through a cock 24. To allow the internal pressure of the pressure sensor to be adjusted freely.
  • reference numeral 25 denotes an insulating silicone agent
  • reference numeral 26 denotes a lead wire.
  • FIG. 4 shows a wide range from Equation 1 OPa to Equation 1 00 Pa
  • FIG. 5 shows a range from practical 50 Pa to 200 Pa in FIG. It is shown enlarged.
  • the results shown in these figures show that the relationship between the discharge starting voltage and the internal pressure of the sensor vessel changes according to Passen's law, which can be the basis for estimating the internal pressure of the pressure sensor according to the present invention. Is well shown.
  • the peak value of the current in one-pulse discharge is about 2.5 mA (25 V / 10 X 10 13 ⁇ ⁇ ), and the average time is about 5 mA. // seconds. This was converted to an average current of 12.5 nA. Naturally, no needle touch was observed even when measured with a 10-meter full-scale ammeter. Conversely, if pulses of the same waveform occur intermittently, for example, a discharge current of 1 mm is observed, then 80 discharge pulses are generated per second, and the average pulse in that case The interval time, that is, the period T was 12.5 milliseconds, and the next pulse discharge was almost certainly stopped by an electromagnetic relay with an operation time of 1.5 milliseconds. By the way, the energy per pulse at this time is 0.313 J, which is about this level. It is unlikely that the energy will damage the IC circuit.
  • the permissible maximum leak rate Sm is about 1.0X 10 ⁇ —5P (P a 'c cZ seconds) due to the life of this type of pressure sensor (about 20 years).
  • Fig. 7 shows the relationship between the number of days and pressure change when a leak occurs at this allowable maximum leak rate Sm. From FIG. 7, it can be seen that if the internal volume V of the pressure sensor is, for example, 0.5 cc, there is a pressure rise of about 25 Pa or more in two weeks.
  • the pressure measurement range it is desirable to set the pressure measurement range to about 20 Pa to 100 Pa. If the pressure is 20 Pa or less, the internal pressure of one sensor does not reach 50 Pa even after about 2 weeks, and even if a high voltage of about 1500 V is applied, no discharge occurs, and the vacuum leakage rate is reduced. Estimation may not be possible. Conversely, if the pressure is 100 Pa or more, even if the internal pressure of one sensor container becomes 125 Pa after about two weeks, the change in the firing voltage at that time is small and within the error range. However, there is a possibility that the vacuum leak rate cannot be estimated.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Biomedical Technology (AREA)
  • Examining Or Testing Airtightness (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

L'invention concerne un procédé permettant de déterminer une acceptation/ un rejet de capteurs de pression (1) de type à jauge de contrainte en fonction de fuites, dans lequel le capteur de pression (1) mesure la pression au moyen d'une tension de contrainte résultant de la différence entre le vide à l'intérieur du boîtier de capteur et une pression appliquée à une partie d'introductio n de pression. Lorsqu'un contrôle est effectué en vue d'une telle détermination, une haute tension en courant continu est appliquée entre une borne (2a) afin de court-circuiter toutes les électrodes (2), et un boîtier métallique (6), au moyen d'une alimentation électrique (8), en vue produire une haute tension en courant continu. Une résistance (7) dotée d'une valeur de résistance élevée, sélectionnée pour empêcher qu'un courant de décharge ne détruise un circuit intégré IC situé à l'intérieur du boîtier métallique (6), est insérée entre la borne positive de l'alimentation électrique (8) et la borne (2a). La haute tension en courant continu provenant de l'alimentation électrique (8) est commandée par un ordinateur (13). La tension est modifiée lentement au début, puis est coupée après une décharge d'une impulsion. La pression de vide à l'intérieur du boîtier métallique (6) est mesurée à partir du courant de décharge Id égal à une impulsion selon la loi de Paschen. Cette mesure est répétée à des intervalles de deux semaines, par exemple, et un rapport de modification de pression moyen est déterminé durant cette période. Si ce rapport de modification de pression est supérieur à une valeur préétablie, le produit est rejeté pour cause de fuite.
PCT/JP1996/003601 1996-12-09 1996-12-09 Procede permettant de determiner une acceptation/ un rejet d'un capteur de pression WO1998026266A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP1996/003601 WO1998026266A1 (fr) 1996-12-09 1996-12-09 Procede permettant de determiner une acceptation/ un rejet d'un capteur de pression
PCT/JP1997/001627 WO1998026267A1 (fr) 1996-12-09 1997-05-14 Procede servant a determiner l'etat defectueux d'un capteur de pression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP1996/003601 WO1998026266A1 (fr) 1996-12-09 1996-12-09 Procede permettant de determiner une acceptation/ un rejet d'un capteur de pression

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WO1998026266A1 true WO1998026266A1 (fr) 1998-06-18

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PCT/JP1996/003601 WO1998026266A1 (fr) 1996-12-09 1996-12-09 Procede permettant de determiner une acceptation/ un rejet d'un capteur de pression
PCT/JP1997/001627 WO1998026267A1 (fr) 1996-12-09 1997-05-14 Procede servant a determiner l'etat defectueux d'un capteur de pression

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PCT/JP1997/001627 WO1998026267A1 (fr) 1996-12-09 1997-05-14 Procede servant a determiner l'etat defectueux d'un capteur de pression

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001501830A (ja) * 1996-10-10 2001-02-13 ライフ テクノロジーズ，インコーポレイテッド 植物由来栄養素を含む動物細胞培養培地

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105352656A (zh) * 2014-07-30 2016-02-24 无锡华润上华半导体有限公司 压力传感器测试装置及其测试方法
CN113050172B (zh) * 2021-03-12 2022-05-24 中国电建集团贵阳勘测设计研究院有限公司 一种渣库渗漏通道的电流场测试方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53104846A (en) * 1977-02-24 1978-09-12 Fujitsu Ltd Leakage check method for reed switch
JPS5723833A (en) * 1980-07-18 1982-02-08 Hitachi Ltd Pressure sensor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53104846A (en) * 1977-02-24 1978-09-12 Fujitsu Ltd Leakage check method for reed switch
JPS5723833A (en) * 1980-07-18 1982-02-08 Hitachi Ltd Pressure sensor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001501830A (ja) * 1996-10-10 2001-02-13 ライフ テクノロジーズ，インコーポレイテッド 植物由来栄養素を含む動物細胞培養培地

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WO1998026267A1 (fr) 1998-06-18

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