Abstract: 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.

Abstract: 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.

Abstract: The present invention provides a method for leak testing by which occurrence of fine leakage from a work as a test object can be determined without being affected by a released tracer gas that is also released from a non-defective work. The method for leak testing includes a series of steps including a gas bombing step wherein a work W as a test object is soaked in a pressurized tracer gas, a work setting step wherein the work subjected to the gas bombing is set in a hermetically sealed container 10, a vacuum suctioning step wherein the hermetically sealed container 10 is vacuum suctioned by a suction device 20 and a measuring step wherein tracer gas measurement data are obtained by measuring a vacuum suctioned tracer gas with a detector 30. Tracer gas measurement data for a non-defective work are preliminarily obtained by performing the series of steps for the non-defective work having same specifications as the work W as the test object.

Abstract: A method for leak testing includes a leak testing step and a reference leak step. In the leak testing step, a hollow work 20 as a test object is encapsulated in a work capsule 11. A test pressure is supplied to the work capsule 11 through a path 2a connected to the work capsule. A variation of pressure inside the work capsule 11 is detected in a condition in which the path 2a is 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 device 30 having a known pinhole 31a is mounted on a work 20? for reference leakage that is same as the work 20 as the test object. The work 20? for reference leakage is encapsulated in the work capsule 11. The test pressure is supplied to the work capsule 11 via the path 2a, and a reference leakage is generated in the work 20? for reference leakage via the reference leak device 30 in a condition in which the path 2a is shut-off.

Abstract: 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 object 9A with a sealing defect 9g, 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 leak 9B having a similar artificial leak device 29 disposed therein, conducting the leak-detected substance is measured. The similar artificial leak device 29 has 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 object 9 is evaluated based on a threshold value set with a standard artificial leak device 9S having the allowable limit conductance.

Abstract: A method for leak testing includes a leak testing step and a reference leak step. In the leak testing step, a hollow work 20 as a test object is encapsulated in a work capsule 11. A test pressure is supplied to the work capsule 11 through a path 2a connected to the work capsule. A variation of pressure inside the work capsule 11 is detected in a condition in which the path 2a is 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 device 30 having a known pinhole 31a is mounted on a work 20? for reference leakage that is same as the work 20 as the test object. The work 20? for reference leakage is encapsulated in the work capsule 11. The test pressure is supplied to the work capsule 11 via the path 2a, and a reference leakage is generated in the work 20? for reference leakage via the reference leak device 30 in a condition in which the path 2a is shut-off.

Abstract: It is an object of the present invention to provide same results of leak judgments even if conditions such as temperature and pressure vary as long as sizes of sealing defects are same. A leak device 5 that generates regular leakage under regular temperature and pressure is made communicable with a test path 19 through which a test pressure is provided. A device actual measurement leak value of the leak device 5 is actually measured by a leakage measuring instrument 33. An object actual measurement leak value of a test object 9 is actually measured by the leakage measuring instrument 33. The object actual measurement leak value is converted into a regular-conditions-converted leak value based on the device actual measurement leak value and a leakage is judged based on the regular-conditions-converted leak value.

Abstract: A method for leak testing includes a leak testing step and a reference leak step. In the leak testing step, a hollow work 20 as a test object is encapsulated in a work capsule 11. A test pressure is supplied to the work capsule 11 through a path 2a connected to the work capsule. A variation of pressure inside the work capsule 11 is detected in a condition in which the path 2a is 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 device 30 having a known pinhole 31a is mounted on a work 20? for reference leakage that is same as the work 20 as the test object. The work 20? for reference leakage is encapsulated in the work capsule 11. The test pressure is supplied to the work capsule 11 via the path 2a, and a reference leakage is generated in the work 20? for reference leakage via the reference leak device 30 in a condition in which the path 2a is shut-off.

Abstract: In leak testing by an accumulation method, it is possible to reliably detect accumulated inspection gas, and the reliability of leak testing is enhanced by reduction in background or impurity gas. At least an openable/closeable part 29 of a capsule 20 is housed inside a chamber 10 of a leak testing apparatus 1. A test workpiece 9 is housed in the capsule 20. Gas inside the chamber 10 is evacuated by a vacuum pump 31. A detector 2 detects inspection gas contained in this gas. The capsule 20 is continuously sealed for an accumulation time Ta, the capsule 20 is thereafter opened, and a leak is evaluated on the basis of detection information after the opening by the detector 2.

Abstract: In leak testing by an accumulation method, it is possible to reliably detect accumulated inspection gas, and the reliability of leak testing is enhanced by reduction in background or impurity gas. At least an openable/closeable part 29 of a capsule 20 is housed inside a chamber 10 of a leak testing apparatus 1. A test workpiece 9 is housed in the capsule 20. Gas inside the chamber 10 is evacuated by a vacuum pump 31. A detector 2 detects inspection gas contained in this gas. The capsule 20 is continuously sealed for an accumulation time Ta, the capsule 20 is thereafter opened, and a leak is evaluated on the basis of detection information after the opening by the detector 2.

Abstract: A leak testing apparatus 1 includes a heat sensitive member 70 having a body 71 made of a material having high thermal conductivity. The body 71 is abutted against an outer surface of a workpiece 10 to close an opening of an inner space 11 of the workpiece 10. A pressure chamber 73 is formed inside the body 71 as arranged along the outer surface and as arranged over an area wider than the opening. Pressurized gas is introduced to the pressure chamber 73. Data on pressure change in the inner space 11 of the workpiece 10 is compensated based on inner pressure information regarding the pressure chamber 73, and leak judgment is made.

Abstract: A leak testing apparatus is provided by which temperature change can be surely detected even when an inner space of a workpiece is narrow. A body 71 of a heat sensitive member 70, made of a material having high thermal conductivity, is abutted against an outer surface of a workpiece 10 to close an opening of an inner space 11 of the workpiece 10. A pressure chamber 73 is formed inside the body 71 as arranged along the outer surface and as arranged over an area wider than the opening. Pressurized gas is introduced to the pressure chamber 73. Data on pressure change in the inner space 11 of the workpiece 10 is compensated based on inner pressure information regarding the pressure chamber 73, and leak judgment is made.