Fukuda Co., Ltd.

National Institute of Advanced Industrial Science and Technology

Mao Hirata

Tsutomu Hara

Naoto Izumo

Masaharu Sugihara

Hajime Yoshida

Akimitsu Tanabe

Masakazu Ito

Kenta Arai

Jun Inomata

Yoshinori Takei

Yasuhiko Higuchi

Yuho Matsui

A leak test condition design method includes obtaining an internal volume of a test piece and a remaining internal volume of a test piece capsule with the test piece loaded for a differential pressure based air leak test; determining a test air pressure to be applied into the test piece capsule when the differential pressure based air leak test is performed; determining bombing conditions of a helium leak test; obtaining a differential pressure value between a test piece and a master to be gained when the differential pressure based air leak test is performed and converting into an equivalent standard leak rate to derive a differential pressure conversion value; obtaining a helium leak rate of the test piece gained and converting into an equivalent standard leak rate to derive a helium leak rate conversion value; and displaying the derived differential pressure conversion value and helium leak rate conversion value.

Leak test condition design method, leak test condition design device, leak testing method, and leak testing device

A flow rate of a gas is determined based on a predetermined relational expression including, as parameters: the flow rate of the gas; diameter and length of a hole; upstream and downstream pressures; and temperature, molecular weight, viscosity coefficient, and specific heat ratio of the gas. Additionally, setting conditions for a type and temperature of the gas, the length of the hole, and the pressures upstream and downstream from the hole are set; the relational expression is used to obtain the correspondence relationship between the diameter of the hole and the flow rate of the gas flowing through the hole; an approximation function approximating the obtained correspondence relationship is determined; the flow rate of a gas passing through a test piece having a hole of an unknown diameter is measured; and the diameter of the hole is estimated, based on the measured flow rate and the approximation function.

Gas flow estimation method, hole diameter estimation method, gas flow rate estimation device, and hole diameter estimation device

A method for leak testing includes a leak testing step and a reference leak step. In the leak testing step, a hollow workas a test object is encapsulated in a work capsule. A test pressure is supplied to the work capsulethrough a pathconnected to the work capsule. A variation of pressure inside the work capsuleis detected in a condition in which the pathis shut-off, and a judgment is made whether a leakage through the work is generated based on the detected output. In the reference leak step, a reference leak devicehaving a known pinholeis mounted on a work′ for reference leakage that is same as the workas the test object. The work′ for reference leakage is encapsulated in the work capsule. The test pressure is supplied to the work capsulevia the path, and a reference leakage is generated in the work′ for reference leakage via the reference leak devicein a condition in which the pathis shut-off. A variation of pressure inside the work capsuleaccompanying the reference leakage is detected.

Method for leak testing and reference leak device for leak testing

It is an object of the present invention to enhance reliability of an allowable limit conductance used for setting a threshold value for evaluating sealability of a test object, and further, enhance reliability of the sealability evaluation. By leak testing a test objectA with a sealing defect, a leakage characteristic that shows a relationship between an internal-external pressure difference and a leak flow rate is obtained. A conductance of a test object with a similar artificial leakB having a similar artificial leak devicedisposed therein, conducting the leak-detected substance is measured. The similar artificial leak devicehas a leakage characteristic similar to the obtained leakage characteristic. An allowable limit conductance is obtained based on results of the measurement. Sealability of a test objectis evaluated based on a threshold value set with a standard artificial leak deviceS having the allowable limit conductance.

Sealability evaluation method and the like and standard artificial leak device

A method for leak testing includes a leak testing step and a reference leak step. In the leak testing step, a hollow workas a test object is encapsulated in a work capsule. A test pressure is supplied to the work capsulethrough a pathconnected to the work capsule. A variation of pressure inside the work capsuleis detected in a condition in which the pathis shut-off, and a judgment is made whether a leakage through the work is generated based on the detected output. In the reference leak step, a reference leak devicehaving a known pinholeis mounted on a work' for reference leakage that is same as the workas the test object. The work&#x2032; for reference leakage is encapsulated in the work capsule. The test pressure is supplied to the work capsulevia the path, and a reference leakage is generated in the work&#x2032; for reference leakage via the reference leak devicein a condition in which the pathis shut-off. A variation of pressure inside the work capsuleaccompanying the reference leakage is detected.

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Tokyo, Japan

Mao Hirata